diff --git a/typo3/sysext/core/Classes/Composer/PackageArtifactBuilder.php b/typo3/sysext/core/Classes/Composer/PackageArtifactBuilder.php
index e959d2a59728fefd61b5f179dc33e71cb2b0b033..597ca7d59d72f5a31e181ae01a8d64c747e00987 100644
--- a/typo3/sysext/core/Classes/Composer/PackageArtifactBuilder.php
+++ b/typo3/sysext/core/Classes/Composer/PackageArtifactBuilder.php
@@ -81,7 +81,7 @@ class PackageArtifactBuilder extends PackageManager implements InstallerScript
         $this->event = $event;
         $this->config = Config::load($this->event->getComposer(), $this->event->getIO());
         $composer = $this->event->getComposer();
-        $basePath = Config::load($composer)->get('base-dir');
+        $basePath = $this->config->get('base-dir');
         $this->packagesBasePath = $basePath . '/';
         foreach ($this->extractPackageMapFromComposer() as [$composerPackage, $path, $extensionKey]) {
             $packagePath = PathUtility::sanitizeTrailingSeparator($path);
@@ -93,7 +93,7 @@ class PackageArtifactBuilder extends PackageManager implements InstallerScript
         }
         $this->sortPackagesAndConfiguration();
         $cacheIdentifier = md5(serialize($composer->getLocker()->getLockData()));
-        $this->setPackageCache(new ComposerPackageArtifact($this->config->get('app-dir') . '/var', new Filesystem(), $cacheIdentifier));
+        $this->setPackageCache(new ComposerPackageArtifact($composer->getConfig()->get('vendor-dir') . '/typo3', new Filesystem(), $cacheIdentifier));
         $this->saveToPackageCache();
 
         return true;
diff --git a/typo3/sysext/core/Classes/Core/Bootstrap.php b/typo3/sysext/core/Classes/Core/Bootstrap.php
index cf1bcba4ac936489e1e544b7c66f6339c9a2d6e6..b42c83acd424f43a309587cae03314266829f548 100644
--- a/typo3/sysext/core/Classes/Core/Bootstrap.php
+++ b/typo3/sysext/core/Classes/Core/Bootstrap.php
@@ -16,6 +16,7 @@
 namespace TYPO3\CMS\Core\Core;
 
 use Composer\Autoload\ClassLoader;
+use Composer\InstalledVersions;
 use Doctrine\Common\Annotations\AnnotationReader;
 use Doctrine\Common\Annotations\AnnotationRegistry;
 use Psr\Container\ContainerInterface;
@@ -268,7 +269,12 @@ class Bootstrap
             return new PackageStatesPackageCache(Environment::getLegacyConfigPath() . '/PackageStates.php', $coreCache);
         }
 
-        return new ComposerPackageArtifact(Environment::getVarPath());
+        $composerInstallersPath = InstalledVersions::getInstallPath('typo3/cms-composer-installers');
+        if ($composerInstallersPath === null) {
+            throw new \RuntimeException('Package "typo3/cms-composer-installers" not found. Replacing the package is not allowed. Fork the package instead and pull in the fork with the same name.', 1636145677);
+        }
+
+        return new ComposerPackageArtifact(dirname($composerInstallersPath));
     }
 
     /**
diff --git a/typo3/sysext/core/Classes/Core/SystemEnvironmentBuilder.php b/typo3/sysext/core/Classes/Core/SystemEnvironmentBuilder.php
index bf4294a70d95b38841a7204fc3a538052387f886..6ab6e11b8e7b3debba9c5546a654cbff144fe513 100644
--- a/typo3/sysext/core/Classes/Core/SystemEnvironmentBuilder.php
+++ b/typo3/sysext/core/Classes/Core/SystemEnvironmentBuilder.php
@@ -220,7 +220,7 @@ class SystemEnvironmentBuilder
         Environment::initialize(
             static::createApplicationContext(),
             self::isCliRequestType($requestType),
-            self::usesComposerClassLoading(),
+            static::usesComposerClassLoading(),
             $isDifferentRootPath ? $projectRootPath : $sitePath,
             $sitePath,
             $isDifferentRootPath ? $projectRootPath . '/var'    : $sitePath . '/typo3temp/var',
diff --git a/typo3/sysext/core/Classes/Package/Cache/ComposerPackageArtifact.php b/typo3/sysext/core/Classes/Package/Cache/ComposerPackageArtifact.php
index 50002bf237f02373bba454651cb5208a9e2d907e..7737acb8468cc76ded37009427fb7d76fc10f75a 100644
--- a/typo3/sysext/core/Classes/Package/Cache/ComposerPackageArtifact.php
+++ b/typo3/sysext/core/Classes/Package/Cache/ComposerPackageArtifact.php
@@ -31,7 +31,7 @@ class ComposerPackageArtifact implements PackageCacheInterface
     /**
      * Location of the file inside the var folder
      */
-    private const ARTIFACTS_FILE = '/build/PackageArtifact.php';
+    private const ARTIFACTS_FILE = '/PackageArtifact.php';
 
     /**
      * Full filesystem path to the file
@@ -62,9 +62,9 @@ class ComposerPackageArtifact implements PackageCacheInterface
      */
     private ?string $cacheIdentifier;
 
-    public function __construct(string $varPath, ?Filesystem $filesystem = null, string $cacheIdentifier = null)
+    public function __construct(string $packageArtifactsPath, ?Filesystem $filesystem = null, string $cacheIdentifier = null)
     {
-        $this->packageArtifactsFile = $varPath . self::ARTIFACTS_FILE;
+        $this->packageArtifactsFile = $packageArtifactsPath . self::ARTIFACTS_FILE;
         $this->filesystem = $filesystem;
         $this->cacheIdentifier = $cacheIdentifier;
     }
diff --git a/typo3/sysext/core/Documentation/Changelog/11.4/Important-95647-ComposerInstallationsAndExtensionUsage.rst b/typo3/sysext/core/Documentation/Changelog/11.4/Important-95647-ComposerInstallationsAndExtensionUsage.rst
index 98a0d1c39f1d5a2aa39b4957f67734f700a921a1..54ea006763615cb73bf8bfc4adcf907c6ad58014 100644
--- a/typo3/sysext/core/Documentation/Changelog/11.4/Important-95647-ComposerInstallationsAndExtensionUsage.rst
+++ b/typo3/sysext/core/Documentation/Changelog/11.4/Important-95647-ComposerInstallationsAndExtensionUsage.rst
@@ -44,9 +44,16 @@ contain this file e.g. under version control, the file can safely be removed.
 Use the TYPO3 CLI command :shell:`extension:setup` to set up all extensions
 available in Composer.
 
+Package information (like paths or extension meta data) is still stored in and evaluated from
+a file in Composer's :file:`vendor` folder. This file is written after Composer dumps autoload information.
+Make sure all files from that (:file:`vendor`) folder are transferred during a deployment.
+This means no special action compared to previous TYPO3 versions is required regarding the :file:`vendor` folder
+with TYPO3 11 LTS.
+
 .. Important::
-   As a successor, the :file:`var/build/PackageArtifact.php` is used which also
-   needs to be deployed.
+   TYPO3 version 11.5.0 to 11.5.2 stored package information in :file:`var/build/` folder,
+   which previously required this folder to be transferred as well during a deployment.
+   This is not required any more now. Transferring the :file:`vendor` folder is sufficient now.
 
 All extensions are always active
 --------------------------------