diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/Configuration.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/Configuration.rst
new file mode 100644
index 0000000000000000000000000000000000000000..9d922bd86edd6c50c1853325bd29a35c35c7774f
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/Configuration.rst
@@ -0,0 +1,60 @@
+.. include:: /Includes.rst.txt
+
+.. _module-configuration:
+
+==============================
+Configuration
+==============================
+
+The Configuration module allows integrators to view and validate the global
+configuration of TYPO3. The module displays all relevant global variables such
+as TYPO3_CONF_VARS, TCA and many more, in a tree format which is easy to browse
+through. Over time this module got extended to also display the configuration of
+newly introduced features like the middleware stack or the event listeners.
+
+.. include:: /Images/AutomaticScreenshots/Modules/Configuration.rst.txt
+
+.. rst-class:: bignums-attention
+
+1.  Access this module in the TYPO3 backend under
+    :guilabel:`System > Configuration`.
+
+2.  Select the desired configuration entry in the upper menu bar.
+
+3.  To find a configuration setting quickly enter a phrase in the search box.
+
+    Is is also possible to use a regular expression for the search phrase.
+    Click on the dropdown box and enable the :guilabel:`Use regular expression`
+    checkbox.
+
+4.  The configuration tree of the selected entry is displayed.
+
+    Expand and collapse the settings with clicking on the triangle.
+
+The Configuration module displays various configuration settings:
+
+- :ref:`Global configuration <t3coreapi:typo3ConfVars>` (:php:`$GLOBALS['TYPO3_CONF_VARS']`)
+- :doc:`Table configuration array <t3tca:Index>` (:php:`$GLOBALS['TCA']`)
+- :ref:`Table help description <t3coreapi:csh-tca-descr>` (:php:`$GLOBALS['TCA_DESCR']`)
+- :ref:`Registered services <t3coreapi:services>` (:php:`$GLOBALS['T3_SERVICES']`)
+- :ref:`Backend modules <t3coreapi:backend-modules>` (:php:`$GLOBALS['TBE_MODULES']`)
+- :ref:`BE modules extensions <t3coreapi:hooks-modules>` (:php:`$GLOBALS['TBE_MODULES_EXT']`)
+- :doc:`Skinning styles <t3skinning:Index>` (:php:`$GLOBALS['TBE_STYLES']`)
+- :ref:`User settings configuration <t3coreapi:user-settings>` (:php:`$GLOBALS['TYPO3_USER_SETTINGS']`)
+- :ref:`Table permissions by page type <t3coreapi:page-types-intro>` (:php:`$GLOBALS['PAGES_TYPES']`)
+- :ref:`User settings <t3coreapi:be-user-configuration>` (:php:`$GLOBALS['BE_USER']->uc`)
+- :ref:`User TSconfig <t3tsconfig:usertsconfig>` (:php:`$GLOBALS['BE_USER']->getTSConfig()`)
+- :ref:`Backend routes <t3coreapi:backend-routing>`
+- :ref:`HTTP Middlewares (PSR-15) <t3coreapi:request-handling>`
+- :ref:`Site configuration <t3coreapi:sitehandling>`
+- :ref:`Event listeners (PSR-14) <t3coreapi:EventDispatcher>`
+- :ref:`MFA providers <t3coreapi:multi-factor-authentication>`
+- :ref:`Soft Reference Parsers <t3coreapi:soft-references>`
+- :ref:`Form: YAML Configuration <ext_form:concepts-configuration>` (with installed :doc:`Form system extension <ext_form:Index>`)
+
+
+Extending the Configuration module
+==================================
+
+The Configuration module can be extended by third-party extensions. Have a look
+into the :ref:`t3coreapi:config-module` chapter in TYPO3 Explained.
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck.rst
new file mode 100644
index 0000000000000000000000000000000000000000..97988c120ef7983fe46633043002b9ed79b0381e
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck.rst
@@ -0,0 +1,76 @@
+.. include:: /Includes.rst.txt
+
+.. _module-db-check:
+
+=========================
+DB Check
+=========================
+
+Access this module in the TYPO3 backend under :guilabel:`System > DB Check`.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check.rst.txt
+
+
+.. container:: row m-0 p-0
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Record statistics <module-db-check-Records-Statistics>`
+
+         .. container:: card-body
+
+            Gives you an overview of how many pages of which type and how many
+            records of any table are present in the current system.
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Database Relations <module-db-check-Database-Relations>`
+
+         .. container:: card-body
+
+            Gives an overview of the count of lost relations in select and group
+            fields
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Full Search <module-db-check-full-search>`
+
+         .. container:: card-body
+
+            Search the complete database or specific table / field combinations
+            and offers you detail and edit links to jump directly to the records
+            found.
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Manage Reference Index <module-db-check-Manage-Reference-Index>`
+
+         .. container:: card-body
+
+            Can be used on smaller installations to check or update the
+            reference index.
+
+.. toctree::
+    :hidden:
+    :titlesonly:
+
+    DbCheck/RecordsStatistics
+    DbCheck/DatabaseRelations
+    DbCheck/FullSearch
+    DbCheck/ManageReferenceIndex
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/DatabaseRelations.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/DatabaseRelations.rst
new file mode 100644
index 0000000000000000000000000000000000000000..5d07a363902b5811c43af499a79f41171af00621
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/DatabaseRelations.rst
@@ -0,0 +1,15 @@
+.. include:: /Includes.rst.txt
+
+.. _module-db-check-Database-Relations:
+
+==================
+Database Relations
+==================
+
+Users with administrator rights can find this module at
+:guilabel:`System > DB Check > Database Relations`.
+
+The module gives some overview of missing relations in fields of the TCA types
+:ref:`select <t3tca:columns-select>` and :ref:`group <t3tca:columns-group>`.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.rst.txt
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/FullSearch.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/FullSearch.rst
new file mode 100644
index 0000000000000000000000000000000000000000..3bf1d05489350698a25bf1234436166b29283b2f
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/FullSearch.rst
@@ -0,0 +1,59 @@
+.. include:: /Includes.rst.txt
+
+.. _module-db-check-full-search:
+
+=================================================
+Full Search
+=================================================
+
+Users with administrator rights can find this module at
+:guilabel:`System > DB Check > Full Search`.
+
+Raw search of all fields
+========================
+
+This module offers a :guilabel:`raw search of all fields`. Here you can enter
+a string and do a raw search.
+
+The result is grouped by record type and there are buttons to edit or get to
+the info of each record.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Full_search.rst.txt
+
+Advanced query
+==============
+
+If you select the option :guilabel:`Advanced query` you can choose the table
+to search and search in different fields.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.rst.txt
+
+Chose a table to search in. Then you can search for certain fields. The GUI
+will let you choose from values that can be entered according to the
+:doc:`TCA <t3tca:Index>`.
+
+For example you can search in table :guilabel:`Page Content`
+(SQL table :sql:`tt_content`) for content elements of a certain type, stored in
+data base field :guilabel:`Type`, SQL field :sql:`CType`. A drop down gives you
+options on the search mode (equals, contains, is in list, ...) and another
+drop down lets you choose the value to search for. In this case it lists all
+available content element types.
+
+You can select more options like group by, order by and limit.
+
+It is also possible to save and load queries. The queries will be saved
+serialized in the column :sql:`uc` of table :sql:`be_users`. It can therefore
+not be shared between users.
+
+Just like in the raw search there are buttons to edit or get to
+the info of each record.
+
+The :guilabel:`Advanced query` action can be
+:ref:`configured with user TSconfig <configuration-full-search>`.
+
+Example
+-------
+
+Search for content elements of type "Header":
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.rst.txt
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/ManageReferenceIndex.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/ManageReferenceIndex.rst
new file mode 100644
index 0000000000000000000000000000000000000000..f2aa4b52527909c2a6161375b2a0e98e04c47c8d
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/ManageReferenceIndex.rst
@@ -0,0 +1,21 @@
+.. include:: /Includes.rst.txt
+
+.. _module-db-check-Manage-Reference-Index:
+
+============================================================
+Manage Reference Index
+============================================================
+
+Users with administrator rights can find this module at
+:guilabel:`System > DB Check > Manage Reference Index`.
+
+In TYPO3 installations with a small number of records this module can be used
+to :ref:`check or update the reference index <t3install:update_reference_index>`.
+
+On TYPO3 installations with a large number of records and many relations between
+those the maximum run time of PHP will be reached and the scripts therefore
+fail. It is recommended to run the commands from the command line then. This
+module outputs the commands with absolute paths to update or check the the
+reference from the command line.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.rst.txt
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/RecordsStatistics.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/RecordsStatistics.rst
new file mode 100644
index 0000000000000000000000000000000000000000..213b4cc8f25cc7eb901cca6d1d367ce4ebac41cf
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/DbCheck/RecordsStatistics.rst
@@ -0,0 +1,14 @@
+.. include:: /Includes.rst.txt
+
+.. _module-db-check-Records-Statistics:
+
+==================
+Records Statistics
+==================
+
+Users with administrator rights can find this module at
+:guilabel:`System > DB Check > Records Statistics`.
+
+This module gives an overview of the count of records of different types.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.rst.txt
diff --git a/typo3/sysext/lowlevel/Documentation/BackendModules/Index.rst b/typo3/sysext/lowlevel/Documentation/BackendModules/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..4734096da0830b8657d92d324d8a0850f4702656
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/BackendModules/Index.rst
@@ -0,0 +1,45 @@
+.. include:: /Includes.rst.txt
+
+.. _backend-modules:
+
+===============
+Backend modules
+===============
+
+The Lowlevel system extension provides two backend modules:
+
+.. container:: row m-0 p-0
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`DB Check <module-db-check>`
+
+         .. container:: card-body
+
+            Offers modules that search or give statistics about the database.
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Configuration <module-configuration>`
+
+         .. container:: card-body
+
+            Gives insights into different configuration values. In cases where
+            the final configuration gets combined at different levels this
+            module can be used to debug the final output. Configuration values
+            cannot be changed in this module.
+
+.. toctree::
+    :hidden:
+    :titlesonly:
+
+    DbCheck
+    Configuration
diff --git a/typo3/sysext/lowlevel/Documentation/CommandLine/Index.rst b/typo3/sysext/lowlevel/Documentation/CommandLine/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..b4f43a2f58cd385ec1471c64e02d977b0da033d1
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/CommandLine/Index.rst
@@ -0,0 +1,168 @@
+.. include:: /Includes.rst.txt
+
+.. _command-line:
+
+============
+Command line
+============
+
+Preparations
+============
+
+.. warning::
+    **THERE IS ABSOLUTELY NO WARRANTY** associated with this script! It is completely on
+    your OWN RISK that you run it. It may cause accidental data loss due to software
+    bugs or circumstances that it does not know about yet - or data loss might
+    happen due to misuse!
+
+**Always** make a complete backup of your website! That means:
+
+* Dump the complete database to an SQL file. This can usually be done from the
+  command line like this::
+
+    mysqldump [database name] -u [database user] -p --add-drop-table > ./mywebsite.sql
+
+* Save all files in the webroot of your site. This can be achieved  from the
+  command line like this::
+
+	tar czf ./mywebsite.tgz [webroot directory of your site]
+
+It could be a good idea to run a `myisamchk` on your database just to make sure
+MySQL has everything pulled together right.
+
+Something like this will do::
+
+	myisamchk [path_to_mysql_databases]/[database_name]/*.MYI -s -r
+
+
+Running the script
+==================
+
+The "[base command]" is::
+
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3
+
+Try this first. If it all works out you should see a help-screen. Otherwise
+there will be instructions about what to do.
+
+You can use the script entirely by following the help screens. However, through
+this document you get some idea about the best order of events since they may
+affect each other.
+
+For each of the tools in the test you can see a help screen by running::
+
+	[base command] --help [toolkey]
+
+Example with the tool "orphan_records"::
+
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 --help cleanup:orphanrecords
+
+
+Suggested order of clean up
+---------------------------
+
+The suggested order below assumes that you are interested in running all these
+tests. Maybe you are not! So you should check the description of each one and if
+there is any of the tests you wish not to run, just leave it out.
+
+It kind of gets simpler that way since the complexity mostly is when you wish to
+run all tests successively in which case there is an optimal order that ensures
+you don't have to run the tests all over again.
+
+- `[base command] cleanup:orphanrecords`
+
+  - As a beginning, get all orphaned records out of the system since you
+    probably want to. Since orphan records may keep some missing relations from
+    being detected it's a good idea to get them out immediately.
+
+- `[base command] cleanup:multiplereferencedfiles`
+
+  - Fix any files referenced twice or more before you delete records (which
+    could potentially delete a file that is referenced by another file).
+
+- `[base command] cleanup:deletedrecords`
+
+  - Flush deleted records. As a rule of thumb, tools that create deleted records
+    should be run before this one so the deleted records they create are also
+    flushed (if you like to of course).
+
+- `[base command] cleanup:missingrelations`
+
+  - Remove missing relations at this point.
+  - If you get an error like this: "\TYPO3\CMS\Core\Database\ReferenceIndex::setReferenceValue(): ERROR: No reference
+    record with hash="132ddb399c0b15593f0d95a58159439f" was found!" just run the test again until no errors occur.
+    The reason is that another fixed reference in the same record and field changed the reference index hash. Running
+    the test again will find the new hash string which will then work for you.
+
+- `[base command] cleanup:flexforms`
+
+  - After the "deleted" tool since we cannot clean-up deleted records and to
+    make sure nothing unimportant is cleaned up.
+
+
+Executed anytime
+----------------
+
+These can be executed anytime, however you should wait till all deleted records
+and versions are flushed so you don't waste system resources on fixing deleted
+records.
+
+::
+
+	[base command] cleanup:missingfiles
+	[base command] cleanup:lostfiles
+
+
+Nightly reports of problems in the system
+-----------------------------------------
+
+If you wish to scan your TYPO3 installations for problems with a cronjob or so, a shell script that outputs a
+report could look like this::
+
+	#!/bin/sh
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles --update-refindex -vv --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:missingrelations --update-refindex -vv --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:flexforms -vv --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:missingfiles --update-refindex -vv --dry-run
+	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:lostfiles --update-refindex -vv --dry-run
+
+
+You may wish to change the verbosity level from `-vv` to `-v` as in the case
+above, depending on how important you consider the warnings.
+
+The output can then be put into a logfile so the logging system can report
+errors.
+
+You might also wish to disable tests like "deleted" which would report deleted
+records - something that might not warrant a warning, frankly speaking ...
+
+Example script for checking your installation
+---------------------------------------------
+
+::
+
+    #!/bin/sh
+    ./typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles -vv --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:missingrelations -vv --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:flexforms -vv --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:missingfiles -vv --dry-run
+    ./typo3/sysext/core/bin/typo3 cleanup:lostfiles -vv --dry-run
+
+
+Example script for cleaning your installation
+---------------------------------------------
+
+::
+
+    #!/bin/sh
+    ./typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv
+    ./typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles -vv --update-refindex
+    ./typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v
+    ./typo3/sysext/core/bin/typo3 cleanup:missingrelations -vv --update-refindex
+    ./typo3/sysext/core/bin/typo3 cleanup:flexforms -vv
+    ./typo3/sysext/core/bin/typo3 cleanup:missingfiles --update-refindex
+    ./typo3/sysext/core/bin/typo3 cleanup:lostfiles -vv --update-refindex
diff --git a/typo3/sysext/lowlevel/Documentation/Configuration/Index.rst b/typo3/sysext/lowlevel/Documentation/Configuration/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..290388e874a5c65200a0f118150f788401be7ce1
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Configuration/Index.rst
@@ -0,0 +1,27 @@
+.. include:: /Includes.rst.txt
+
+.. _configuration:
+
+=============
+Configuration
+=============
+
+.. container:: row m-0 p-0
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`TSconfig <configuration-tsconfig>`
+
+         .. container:: card-body
+
+            Configures display and function of the backend modules.
+
+.. toctree::
+    :hidden:
+    :titlesonly:
+
+    TSconfig
diff --git a/typo3/sysext/lowlevel/Documentation/Configuration/TSconfig.rst b/typo3/sysext/lowlevel/Documentation/Configuration/TSconfig.rst
new file mode 100644
index 0000000000000000000000000000000000000000..0299b9974e0aaa0c5ea4e3de4e14d3363d65daf5
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Configuration/TSconfig.rst
@@ -0,0 +1,163 @@
+.. include:: /Includes.rst.txt
+
+.. _configuration-tsconfig:
+
+========
+TSconfig
+========
+
+.. _configuration-full-search:
+
+User TSconfig of the module "Full Search"
+=========================================
+
+The module :ref:`System > DB Check > Full Search <module-db-check-full-search>`
+can be configured with the following
+:ref:`User TSconfig <t3tsconfig:usertsconfig>`.
+
+See also the chapter of :ref:`Setting User TSconfig
+<t3tsconfig:setting-page-tsconfig>`.
+
+.. include:: /Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.rst.txt
+
+.. confval:: disableStoreControl
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    By default administrators can store and load their search configurations.
+
+    Disable the display of the load and save configuration controls:
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableStoreControl = 1
+            disableSelectATable = 0
+        }
+
+.. confval:: disableShowSQLQuery
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    By default the SQL query used for searching the records is displayed
+    for successful searches and in case there are errors.
+
+    If this option is set to true the raw SQL query of the search is
+    not displayed in either case:
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableShowSQLQuery = 1
+        }
+
+.. confval:: disableSelectATable
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    If this option is set to true the affected administrators cannot select a
+    table in which to search. This makes sense when there are prepared saved
+    queries that should be used by the administrator but she should not be able
+    to create new ones. If set to true :confval:`disableStoreControl` should be
+    set to false, otherwise the module
+    :guilabel:`System > DB Check > Full Search > Advanced query` cannot be used
+    at all by the affected administrator.
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableStoreControl = 0
+            disableSelectATable = 1
+        }
+
+.. confval:: disableSelectFields
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    By default the fields :sql:`uid` and the field specified as
+    :ref:`label in the TCA <t3tca:columns-properties-label>` are selected by
+    default. The users can choose different fields to be selected.
+
+    By setting this configuration value to true the user can only use the
+    default fields or the fields specified by a saved query and cannot change
+    them.
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableSelectFields = 1
+        }
+
+.. confval:: disableMakeQuery
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    Disables the :guilabel:`Make Query` section. Results cannot be filtered
+    by fields then, unless saved queries are provided.
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableMakeQuery = 1
+        }
+
+.. confval:: disableGroupBy
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    Disables the group by functionality.
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableGroupBy = 1
+        }
+
+.. confval:: disableOrderBy
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    Disables the order by functionality.
+
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableOrderBy = 1
+        }
+
+.. confval:: disableLimit
+
+    :Path: mod.dbint
+    :type: bool
+    :Default: false
+
+    Disables changing the limit. The default limit is 100 records.
+
+    .. code-block:: typoscript
+        :caption: User TSconfig
+
+        mod.dbint {
+            disableLimit = 1
+        }
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.png
new file mode 100644
index 0000000000000000000000000000000000000000..7d799f6ee0d4c9eeeaa1b357667520ff2a9ab52b
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..8b69e1f04dec2fa3177cfc69957db7584a883a77
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/Configuration.rst.txt
@@ -0,0 +1,10 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/Configuration.png
+   :alt: Overview of the configuration backend module
+   :class: with-shadow
+
+   The :guilabel:`Configuration` module with menu entry (1), Configuration selector (2), Search box (3) and Configuration tree
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.png
new file mode 100644
index 0000000000000000000000000000000000000000..d697cb8141f6ba48bf41595e606e9127313f1d06
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..599a168f585af55101175e9742a303bc8f3881c8
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check.png
+   :class: with-shadow
+
+   The :guilabel:`DB Check` module Overview page
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.png
new file mode 100644
index 0000000000000000000000000000000000000000..d523d397cbee5795c04f4580c1b3232b7a88e841
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..7fd4630dc2b15b15085e6dcbbbe5be055e4d4c93
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query.png
+   :class: with-shadow
+
+   The :guilabel:`Advanced query` action
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.png
new file mode 100644
index 0000000000000000000000000000000000000000..91998e8d650fa7ae6df4a1903ac58a61d25cd899
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..4da9ecc26ad8eea3aee0939bb989bf1b95c40530
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Advanced_query_tt_content.png
+   :class: with-shadow
+
+   Search for content elements of type header only
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.png
new file mode 100644
index 0000000000000000000000000000000000000000..640d44891a7af0c4ee80f93c4dede411787938ee
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..2bb90c90b9b06ed317d8c5cf4af13f1921a71bae
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Database_Relations.png
+   :class: with-shadow
+
+   The :guilabel:`Database Relations` action
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.png
new file mode 100644
index 0000000000000000000000000000000000000000..bf053602e03036d5f67a898e51e062608dc49dd1
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..dcf363e4135d723ffeaf111d436425b39bd4c5fc
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Full_search.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Full_search.png
+   :class: with-shadow
+
+   The :guilabel:`Full search` action
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.png
new file mode 100644
index 0000000000000000000000000000000000000000..86699541ce9e62fb5f21998c6c46d857c891de68
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..68bed73e69f7ae430b4a152d5ce36a82521426de
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Manage_Reference_Index.png
+   :class: with-shadow
+
+   The :guilabel:`Manage Reference Index` action
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.png b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.png
new file mode 100644
index 0000000000000000000000000000000000000000..e2f4891af5d934a1d019622d0316c31eef2fbd71
Binary files /dev/null and b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.png differ
diff --git a/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.rst.txt b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..d9343debf350aa628f3703613b94f7b1431cb9b4
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.rst.txt
@@ -0,0 +1,9 @@
+.. =========================================================
+.. Automatically generated by the TYPO3 Screenshots project.
+.. https://github.com/TYPO3-Documentation/t3docs-screenshots
+.. =========================================================
+
+.. figure:: /Images/AutomaticScreenshots/Modules/DB_Check_Records_Statistics.png
+   :class: with-shadow
+
+   The :guilabel:`Records Statistics` action
\ No newline at end of file
diff --git a/typo3/sysext/lowlevel/Documentation/Includes.rst.txt b/typo3/sysext/lowlevel/Documentation/Includes.rst.txt
new file mode 100644
index 0000000000000000000000000000000000000000..b675887bcfb00d324596aad40d02c871e76492ea
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Includes.rst.txt
@@ -0,0 +1,32 @@
+.. More information about this file:
+.. https://docs.typo3.org/m/typo3/docs-how-to-document/main/en-us/GeneralConventions/FileStructure.html#includes-rst-txt
+
+.. ----------
+.. text roles
+.. ----------
+
+.. role:: aspect(emphasis)
+.. role:: bash(code)
+.. role:: html(code)
+.. role:: js(code)
+.. role:: php(code)
+.. role:: rst(code)
+.. role:: sep(strong)
+.. role:: sql(code)
+
+.. role:: tsconfig(code)
+   :class: typoscript
+
+.. role:: typoscript(code)
+.. role:: xml(code)
+   :class: html
+
+.. role:: yaml(code)
+
+.. default-role:: code
+
+.. ---------
+.. highlight
+.. ---------
+
+.. highlight:: shell
diff --git a/typo3/sysext/lowlevel/Documentation/Index.rst b/typo3/sysext/lowlevel/Documentation/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..43ed1ec124fcc770b3b38152b09eee79f3f28282
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Index.rst
@@ -0,0 +1,94 @@
+.. include:: /Includes.rst.txt
+
+=============================
+Lowlevel (typo3/cms-lowlevel)
+=============================
+
+:Extension key:
+    lowlevel
+
+:Package name:
+    typo3/cms-lowlevel
+
+:Version:
+    |release|
+
+:Language:
+    en
+
+:Author:
+    TYPO3 CMS Core Development Team
+
+:License:
+    This document is published under the
+    `Creative Commons BY 4.0 <https://creativecommons.org/licenses/by/4.0/>`__
+    license.
+
+:Rendered:
+    |today|
+
+The lowlevel extension provides command line scripts for technical analysis of
+the system. This includes raw database search, checking relations, counting
+pages and records etc.
+
+.. container:: row m-0 p-0
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Introduction <introduction>`
+
+         .. container:: card-body
+
+            Gives an introduction on what this extension can be used for. Aims
+            at new system administrators and developers.
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Command line <command-line>`
+
+         .. container:: card-body
+
+            Explains the commands provided by the lowlevel extension and
+            how to use them.
+
+   .. container:: col-md-6 pl-0 pr-3 py-3 m-0
+
+      .. container:: card px-0 h-100
+
+         .. rst-class:: card-header h3
+
+            .. rubric:: :ref:`Backend modules <backend-modules>`
+
+         .. container:: card-body
+
+            Explains the two backend modules
+            :ref:`System > Configuration <module-configuration>` and
+            :ref:`System > DB Check <module-db-check>` provided by this extension.
+
+**Table of Contents:**
+
+.. toctree::
+    :maxdepth: 2
+    :titlesonly:
+
+    Introduction/Index
+    Installation/Index
+    BackendModules/Index
+    CommandLine/Index
+    Configuration/Index
+
+.. Meta Menu
+
+.. toctree::
+    :hidden:
+
+    Sitemap
+    genindex
diff --git a/typo3/sysext/lowlevel/Documentation/Installation/Index.rst b/typo3/sysext/lowlevel/Documentation/Installation/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..ce8c75d19a607ab0701160ef01e3b176ee0cd677
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Installation/Index.rst
@@ -0,0 +1,17 @@
+.. include:: /Includes.rst.txt
+
+.. _installation:
+
+============
+Installation
+============
+
+For :ref:`composer-based TYPO3 installations <t3start:install>`:
+
+.. code-block:: shell
+
+    composer require typo3/cms-lowlevel
+
+For :ref:`legacy installations <t3start:legacyinstallation>` activate the
+:guilabel:`TYPO3 CMS Lowlevel` extension in
+the :ref:`Extension Manager <t3start:extensions_legacy_management>`.
diff --git a/typo3/sysext/lowlevel/Documentation/Introduction/Index.rst b/typo3/sysext/lowlevel/Documentation/Introduction/Index.rst
new file mode 100644
index 0000000000000000000000000000000000000000..20dc3781c54f2dc99d982825aebd4c265dd8eb74
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Introduction/Index.rst
@@ -0,0 +1,34 @@
+.. include:: /Includes.rst.txt
+
+.. _introduction:
+
+============
+Introduction
+============
+
+For various reasons your TYPO3 installation may over time accumulate data with
+integrity problems or data you wish to delete completely. For instance, why keep
+old versions of published content? Keep that in your backup - don't load your
+running website with that overhead!
+
+Or what about deleted records? Why not flush them - they also fill up your
+database and filesystem and most likely you can rely on your backups in case of
+an emergency recovery?
+
+Also, relations between records and files inside TYPO3 may be lost over time for
+various reasons.
+
+If your website runs as it should such "integrity problems" are mostly easy to
+automatically repair by simply removing the references pointing to a missing
+record or file.
+
+However, it might also be "soft references" from eg. internal links
+(:html:`<a href="t3://page?id=123">...</a>`) or a file referenced in a TypoScript
+template (:typoscript:`something.file = fileadmin/template/miss_me.jpg`) which are missing.
+Those cannot be automatically repaired but the cleanup script incorporates
+warnings that will tell you about these problems if they exist and you can
+manually fix them.
+
+These scripts provide solutions to these problems by offering an array of tools
+that can analyze your TYPO3 installation for various problems and in some cases
+offer fixes for them.
diff --git a/typo3/sysext/lowlevel/Documentation/Settings.cfg b/typo3/sysext/lowlevel/Documentation/Settings.cfg
index 5bd2facc723190c81f286b65b37fdcae74548c0f..98e031c535287260aeb160cf11d37d9c9defd09f 100644
--- a/typo3/sysext/lowlevel/Documentation/Settings.cfg
+++ b/typo3/sysext/lowlevel/Documentation/Settings.cfg
@@ -1,21 +1,64 @@
 
-# #####
-#
-# Settings.cfg - A TYPO3 Documentation Project's Configuration File
-# Information about Settings.cfg:
-#   https://docs.typo3.org/m/typo3/docs-how-to-document/main/en-us/GeneralConventions/DirectoryFilenames.html#settings-cfg
-#
-# #####
+# More information about this file:
+# https://docs.typo3.org/m/typo3/docs-how-to-document/main/en-us/GeneralConventions/FileStructure.html#settings-cfg
 
 [general]
 
 project     = lowlevel
+version     = main
+release     = main
+copyright   = since 2015 by the TYPO3 contributors
 
 [html_theme_options]
 
-github_branch        = main
-github_repository    =  typo3/typo3
-path_to_documentation_dir = typo3/sysext/lowlevel
-project_issues       = https://forge.typo3.org/projects/typo3cms-core/issues
+# "Edit on GitHub" button
+github_repository         = typo3/typo3
+github_branch             = main
+
+# Footer links
+project_home         = https://forge.typo3.org/projects/typo3cms-core
+project_contact      = https://typo3.org/help
 project_repository   = https://github.com/typo3/typo3
+project_issues       = https://forge.typo3.org/projects/typo3cms-core/issues
+project_discussions  =
+
+use_opensearch       = 1
+
+[intersphinx_mapping]
+
+# Official TYPO3 manuals
+# h2document     = https://docs.typo3.org/m/typo3/docs-how-to-document/main/en-us/
+# t3cheatsheets  = https://docs.typo3.org/m/typo3/docs-cheatsheets/main/en-us/
+# t3contribute   = https://docs.typo3.org/m/typo3/guide-contributionworkflow/main/en-us/
+t3coreapi      = https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/
+# t3docteam      = https://docs.typo3.org/m/typo3/team-t3docteam/main/en-us/
+# t3editors      = https://docs.typo3.org/m/typo3/tutorial-editors/main/en-us/
+# t3extbasebook  = https://docs.typo3.org/m/typo3/book-extbasefluid/main/en-us/
+# t3extexample   = https://docs.typo3.org/m/typo3/guide-example-extension-manual/main/en-us/
+# t3home         = https://docs.typo3.org/
+t3install      = https://docs.typo3.org/m/typo3/guide-installation/main/en-us/
+# t3l10n         = https://docs.typo3.org/m/typo3/guide-frontendlocalization/main/en-us/
+t3skinning    = https://docs.typo3.org/m/typo3/reference-skinning/main/en-us/
+# t3sitepackage  = https://docs.typo3.org/m/typo3/tutorial-sitepackage/main/en-us/
+t3start        = https://docs.typo3.org/m/typo3/tutorial-getting-started/main/en-us/
+t3tca          = https://docs.typo3.org/m/typo3/reference-tca/main/en-us/
+# t3templating   = https://docs.typo3.org/m/typo3/tutorial-templating/main/en-us/
+# t3translate    = https://docs.typo3.org/m/typo3/guide-frontendlocalization/main/en-us/
+t3tsconfig     = https://docs.typo3.org/m/typo3/reference-tsconfig/main/en-us/
+# t3tsref        = https://docs.typo3.org/m/typo3/reference-typoscript/main/en-us/
+# t3ts45         = https://docs.typo3.org/m/typo3/tutorial-typoscript-in-45-minutes/main/en-us/
+# t3viewhelper   = https://docs.typo3.org/other/typo3/view-helper-reference/main/en-us/
+# t3upgrade      = https://docs.typo3.org/m/typo3/guide-installation/main/en-us/
 
+# TYPO3 system extensions
+# ext_adminpanel     = https://docs.typo3.org/c/typo3/cms-adminpanel/main/en-us/
+# ext_core           = https://docs.typo3.org/c/typo3/cms-core/main/en-us/
+# ext_dashboard      = https://docs.typo3.org/c/typo3/cms-dashboard/main/en-us/
+# ext_felogin        = https://docs.typo3.org/c/typo3/cms-felogin/main/en-us/
+ext_form           = https://docs.typo3.org/c/typo3/cms-form/main/en-us/
+# ext_fsc            = https://docs.typo3.org/c/typo3/cms-fluid-styled-content/main/en-us/
+# ext_indexed_search = https://docs.typo3.org/c/typo3/cms-indexed-search/main/en-us/
+# ext_rte_ckeditor   = https://docs.typo3.org/c/typo3/cms-rte-ckeditor/main/en-us/
+# ext_scheduler      = https://docs.typo3.org/c/typo3/cms-scheduler/main/en-us/
+# ext_seo            = https://docs.typo3.org/c/typo3/cms-seo/main/en-us/
+# ext_workspaces     = https://docs.typo3.org/c/typo3/cms-workspaces/main/en-us/
diff --git a/typo3/sysext/lowlevel/Documentation/Sitemap.rst b/typo3/sysext/lowlevel/Documentation/Sitemap.rst
new file mode 100644
index 0000000000000000000000000000000000000000..09d3c6f56e97422d5e402797988ad9ab0b994777
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/Sitemap.rst
@@ -0,0 +1,9 @@
+:template: sitemap.html
+
+.. include:: /Includes.rst.txt
+
+=======
+Sitemap
+=======
+
+.. The sitemap.html template will insert here the page tree automatically.
diff --git a/typo3/sysext/lowlevel/Documentation/genindex.rst b/typo3/sysext/lowlevel/Documentation/genindex.rst
new file mode 100644
index 0000000000000000000000000000000000000000..806ec56a77c4fd96f61bccba17e471c1d273b5cc
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/genindex.rst
@@ -0,0 +1,7 @@
+.. include:: /Includes.rst.txt
+
+=====
+Index
+=====
+
+.. Sphinx will insert here the general index automatically.
diff --git a/typo3/sysext/lowlevel/Documentation/screenshots.json b/typo3/sysext/lowlevel/Documentation/screenshots.json
new file mode 100644
index 0000000000000000000000000000000000000000..b0ecd36e91c2973b2b8f47086b637cf904181dd2
--- /dev/null
+++ b/typo3/sysext/lowlevel/Documentation/screenshots.json
@@ -0,0 +1,86 @@
+{
+    "suites": {
+        "Styleguide": {
+            "screenshots": {
+				"_default": [
+					{"action": "resizeWindow", "width": 1024, "height": 600},
+					{"action": "setScreenshotsImagePath","path": "Images/AutomaticScreenshots"},
+					{"action": "setScreenshotsRstPath", "path": "Images/AutomaticScreenshots"}
+				],
+				"Configuration": [
+					{"include": "_default"},
+					{"action": "goToModule", "module": "Configuration"},
+					{"action": "switchToMainFrame"},
+					{"action": "drawBadge", "selector": "#system_config", "label": "1", "position": "right"},
+					{"action": "switchToContentFrame"},
+					{"action": "drawBadge", "selector": ".t3-js-jumpMenuBox", "label": "2", "position": "right"},
+					{"action": "drawBadge", "selector": "#lowlevel-searchString", "label": "3", "position": "right"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/Configuration",
+						"altText": "Overview of the configuration backend module",
+						"captionText": "The :guilabel:`Configuration` module with menu entry (1), Configuration selector (2), Search box (3) and Configuration tree"
+					},
+					{"action": "clearDrawings"}
+				],
+				"DB_Check": [
+					{"include": "_default"},
+					{"action": "goToModule", "module": "DB Check"},
+					{"action": "switchToMainFrame"},
+					{"action": "drawBadge", "selector": "#system_dbint", "label": "1", "position": "right"},
+					{"action": "switchToContentFrame"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check",
+						"captionText": "The :guilabel:`DB Check` module Overview page"
+					},
+					{"action": "clearDrawings"},
+					{"action": "click", "link": "Records Statistics"},
+					{"action": "waitForText", "text": "Total number of default language pages"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Records_Statistics",
+						"captionText": "The :guilabel:`Records Statistics` action"
+					},
+					{"action": "selectOption", "select": ".t3-js-jumpMenuBox", "option": "Database Relations"},
+					{"action": "waitForText", "text": "Select fields"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Database_Relations",
+						"captionText": "The :guilabel:`Database Relations` action"
+					},
+					{"action": "selectOption", "select": ".t3-js-jumpMenuBox", "option": "Full search"},
+					{"action": "waitForText", "text": "Search whole Database"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Full_search",
+						"captionText": "The :guilabel:`Full search` action"
+					},
+					{"action": "selectOption", "select": "select[data-menu-identifier=\"search\"]", "option": "Advanced query"},
+					{"action": "waitForText", "text": "Make query"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Advanced_query",
+						"captionText": "The :guilabel:`Advanced query` action"
+					},
+					{"action": "resizeWindow", "width": 1024, "height": 1024},
+					{"action": "selectOption", "select": "select[name=\"SET[queryTable]\"]", "option": "tt_content"},
+					{"action": "waitForText", "text": "Select fields"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Advanced_query_tt_content",
+						"captionText": "Search for content elements of type header only"
+					},
+					{"action": "resizeWindow", "width": 1024, "height": 600},
+					{"action": "selectOption", "select": ".t3-js-jumpMenuBox", "option": "Manage Reference Index"},
+					{"action": "waitForText", "text": "Using the command line interface"},
+					{
+						"action": "makeScreenshotOfWindow",
+						"fileName": "Modules/DB_Check_Manage_Reference_Index",
+						"captionText": "The :guilabel:`Manage Reference Index` action"
+					}
+				]
+            }
+        }
+    }
+}
diff --git a/typo3/sysext/lowlevel/README.rst b/typo3/sysext/lowlevel/README.rst
index 9a0866bf77d17888c64da47ee5d9f448d9cdfb9a..4541384eb526e1de29602c274a8ed449ede6c2f3 100644
--- a/typo3/sysext/lowlevel/README.rst
+++ b/typo3/sysext/lowlevel/README.rst
@@ -1,179 +1,15 @@
-This documentation describes the lowlevel script provided by the TYPO3 system
-extension EXT:lowlevel.
+\|
+`Contributing <https://docs.typo3.org/m/typo3/guide-contributionworkflow/main/en-us/Index.html>`__  \|
+`Help & Support <https://typo3.org/help>`__ \|
 
+=============================
+Lowlevel (typo3/cms-lowlevel)
+=============================
 
-Introduction
-============
-
-For various reasons your TYPO3 installation may over time accumulate data with integrity problems or data you wish
-to delete completely. For instance, why keep old versions of published content? Keep that in your backup - don't load
-your running website with that overhead!
-
-Or what about deleted records? Why not flush them - they also fill up your database and filesystem and most likely you
-can rely on your backups in case of an emergency recovery?
-
-Also, relations between records and files inside TYPO3 may be lost over time for various reasons.
-
-If your website runs as it should such "integrity problems" are mostly easy to automatically repair by simply removing
-the references pointing to a missing record or file.
-
-However, it might also be "soft references" from eg. internal links (`<a href="t3://page?id=123">...</a>`) or a file references in a
-TypoScript template (`something.file = fileadmin/template/miss_me.jpg`) which are missing. Those cannot be automatically
-repaired but the cleanup script incorporates warnings that will tell you about these problems if they exist and you
-can manually fix them.
-
-These scripts provides solutions to these problems by offering an array of tools that can analyze your TYPO3 installation
-for various problems and in some cases offer fixes for them.
-
-
-
-Preparations
-============
-
-THERE IS ABSOLUTELY NO WARRANTY associated with this script! It is completely on your OWN RISK that you run it.
-It may cause accidental data loss due to software bugs or circumstances that it does not know about yet - or data
-loss might happen due to misuse!
-
-ALWAYS make a complete backup of your website! That means:
-
-* Dump the complete database to an SQL file. This can usually be done from the command line like this::
-
-	mysqldump [database name] -u [database user] -p --add-drop-table > ./mywebsite.sql
-
-* Save all files in the webroot of your site. I usually do this from the command line like this::
-
-	tar czf ./mywebsite.tgz [webroot directory of your site]
-
-It could be a good idea to run a `myisamchk` on your database just to make sure MySQL has everything pulled together right.
-
-Something like this will do::
-
-	myisamchk [path_to_mysql_databases]/[database_name]/*.MYI -s -r
-
-
-
-Running the script
-==================
-
-The "[base command]" is::
-
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3
-
-Try this first. If it all works out you should see a help-screen. Otherwise there will be instructions about what to do.
-
-You can use the script entirely by following the help screens. However, through this document you get some idea about
-the best order of events since they may affect each other.
-
-For each of the tools in the test you can see a help screen by running::
-
-	[base command] --help [toolkey]
-
-Example with the tool "orphan_records"::
-
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 --help cleanup:orphanrecords
-
-
-
-Suggested order of clean up
----------------------------
-
-The suggested order below assumes that you are interested in running all these tests. Maybe you are not! So you should
-check the description of each one and if there is any of the tests you wish not to run, just leave it out.
-
-It kind of gets simpler that way since the complexity mostly is when you wish to run all tests successively in which
-case there is an optimal order that ensures you don't have to run the tests all over again.
-
-- `[base command] cleanup:orphanrecords`
-
-  - As a beginning, get all orphaned records out of the system since you probably want to. Since orphan records may
-    keep some missing relations from being detected it's a good idea to get them out immediately.
-
-- `[base command] cleanup:multiplereferencedfiles`
-
-  - Fix any files referenced twice or more before you delete records (which could potentially delete a file that is
-    referenced by another file).
-
-- `[base command] cleanup:deletedrecords`
-
-  - Flush deleted records. As a rule of thumb, tools that create deleted records should be run before this one so
-    the deleted records they create are also flushed (if you like to of course)
-
-- `[base command] cleanup:missingrelations`
-
-  - Remove missing relations at this point.
-  - If you get an error like this; "\TYPO3\CMS\Core\Database\ReferenceIndex::setReferenceValue(): ERROR: No reference
-    record with hash="132ddb399c0b15593f0d95a58159439f" was found!" just run the test again until no errors occur.
-    The reason is that another fixed reference in the same record and field changed the reference index hash. Running
-    the test again will find the new hash string which will then work for you.
-
-- `[base command] cleanup:flexforms`
-
-  - After the "deleted" tool since we cannot clean-up deleted records and to make sure nothing unimportant
-    is cleaned up.
-
-
-Executed anytime
-----------------
-
-These can be executed anytime, however you should wait till all deleted records and versions are flushed so you don't
-waste system resources on fixing deleted records.
-
-::
-
-	[base command] cleanup:missingfiles
-	[base command] cleanup:lostfiles
-
-
-Nightly reports of problems in the system
------------------------------------------
-
-If you wish to scan your TYPO3 installations for problems with a cronjob or so, a shell script that outputs a
-report could look like this::
-
-	#!/bin/sh
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles --update-refindex -vv --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:missingrelations --update-refindex -vv --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:flexforms -vv --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:missingfiles --update-refindex -vv --dry-run
-	[typo3_site_directory]/typo3/sysext/core/bin/typo3 cleanup:lostfiles --update-refindex -vv --dry-run
-
-
-You may wish to change the verbosity level from `-vv` to `-v` as in the case above, depending on how important
-you consider the warnings.
-
-The output can then be put into a logfile so the logging system can report errors.
-
-You might also wish to disable tests like "deleted" which would report deleted records - something that might not
-warrant a warning, frankly speaking...
-
-Example script for checking your installation
----------------------------------------------
-
-::
-
-    #!/bin/sh
-    ./typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles -vv --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:missingrelations -vv --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:flexforms -vv --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:missingfiles -vv --dry-run
-    ./typo3/sysext/core/bin/typo3 cleanup:lostfiles -vv --dry-run
-
-
-Example script for cleaning your installation
----------------------------------------------
-
-::
-
-    #!/bin/sh
-    ./typo3/sysext/core/bin/typo3 cleanup:orphanrecords -vv
-    ./typo3/sysext/core/bin/typo3 cleanup:multiplereferencedfiles -vv --update-refindex
-    ./typo3/sysext/core/bin/typo3 cleanup:deletedrecords -v
-    ./typo3/sysext/core/bin/typo3 cleanup:missingrelations -vv --update-refindex
-    ./typo3/sysext/core/bin/typo3 cleanup:flexforms -vv
-    ./typo3/sysext/core/bin/typo3 cleanup:missingfiles --update-refindex
-    ./typo3/sysext/core/bin/typo3 cleanup:lostfiles -vv --update-refindex
+The lowlevel extension provides command line scripts for technical analysis of
+the system. This includes raw database search, checking relations, counting
+pages and records etc.
 
+:Repository: https://github.com/typo3/typo3
+:Issues: https://forge.typo3.org/
+:Documentation: https://docs.typo3.org/c/typo3/cms-lowlevel/master/en-us