diff --git a/conf/config.neon b/conf/config.neon
index c85cce945d..46f65b6fbb 100644
--- a/conf/config.neon
+++ b/conf/config.neon
@@ -2137,6 +2137,7 @@ services:
 		class: PHPStan\Diagnose\PHPStanDiagnoseExtension
 		arguments:
 			composerAutoloaderProjectPaths: %composerAutoloaderProjectPaths%
+			allConfigFiles: %allConfigFiles%
 		autowired: false
 
 	# Error formatters
diff --git a/src/Diagnose/PHPStanDiagnoseExtension.php b/src/Diagnose/PHPStanDiagnoseExtension.php
index 0873b4f802..8a0834d278 100644
--- a/src/Diagnose/PHPStanDiagnoseExtension.php
+++ b/src/Diagnose/PHPStanDiagnoseExtension.php
@@ -5,13 +5,21 @@
 use Phar;
 use PHPStan\Command\Output;
 use PHPStan\ExtensionInstaller\GeneratedConfig;
+use PHPStan\File\FileHelper;
 use PHPStan\Internal\ComposerHelper;
 use PHPStan\Php\PhpVersion;
+use function array_key_exists;
+use function array_slice;
 use function class_exists;
 use function count;
 use function dirname;
+use function explode;
+use function implode;
 use function is_file;
 use function sprintf;
+use function str_starts_with;
+use function strlen;
+use function substr;
 use const PHP_VERSION_ID;
 
 class PHPStanDiagnoseExtension implements DiagnoseExtension
@@ -19,10 +27,13 @@ class PHPStanDiagnoseExtension implements DiagnoseExtension
 
 	/**
 	 * @param string[] $composerAutoloaderProjectPaths
+	 * @param string [] $allConfigFiles
 	 */
 	public function __construct(
 		private PhpVersion $phpVersion,
+		private FileHelper $fileHelper,
 		private array $composerAutoloaderProjectPaths,
+		private array $allConfigFiles,
 	)
 	{
 	}
@@ -71,6 +82,51 @@ public function print(Output $output): void
 		}
 		$output->writeLineFormatted('');
 
+		$thirdPartyIncludedConfigs = [];
+		foreach ($this->allConfigFiles as $configFile) {
+			$configFile = $this->fileHelper->normalizePath($configFile, '/');
+			foreach ($this->composerAutoloaderProjectPaths as $composerAutoloaderProjectPath) {
+				$composerConfig = ComposerHelper::getComposerConfig($composerAutoloaderProjectPath);
+				if ($composerConfig === null) {
+					continue;
+				}
+				$vendorDir = $this->fileHelper->normalizePath(ComposerHelper::getVendorDirFromComposerConfig($composerAutoloaderProjectPath, $composerConfig), '/');
+				if (!str_starts_with($configFile, $vendorDir)) {
+					continue;
+				}
+
+				$installedPath = $vendorDir . '/composer/installed.php';
+				if (!is_file($installedPath)) {
+					continue;
+				}
+
+				$installed = require $installedPath;
+
+				$trimmed = substr($configFile, strlen($vendorDir) + 1);
+				$parts = explode('/', $trimmed);
+				$package = implode('/', array_slice($parts, 0, 2));
+				$configPath = implode('/', array_slice($parts, 2));
+				if (!array_key_exists($package, $installed['versions'])) {
+					continue;
+				}
+
+				$packageVersion = $installed['versions'][$package]['pretty_version'] ?? null;
+				if ($packageVersion === null) {
+					continue;
+				}
+
+				$thirdPartyIncludedConfigs[] = [$package, $packageVersion, $configPath];
+			}
+		}
+
+		if (count($thirdPartyIncludedConfigs) > 0) {
+			$output->writeLineFormatted('<info>Included configs from Composer packages:</info>');
+			foreach ($thirdPartyIncludedConfigs as [$package, $packageVersion, $configPath]) {
+				$output->writeLineFormatted(sprintf('%s (%s): %s', $package, $configPath, $packageVersion));
+			}
+			$output->writeLineFormatted('');
+		}
+
 		$composerAutoloaderProjectPathsCount = count($this->composerAutoloaderProjectPaths);
 		$output->writeLineFormatted(sprintf(
 			'<info>Discovered Composer project %s:</info>',