diff --git a/.phan/stubs/eventlogging.php b/.phan/stubs/eventlogging.php
index c011c58f..f4f46dff 100644
--- a/.phan/stubs/eventlogging.php
+++ b/.phan/stubs/eventlogging.php
@@ -3,11 +3,6 @@
 namespace MediaWiki\Extension\EventLogging;
 
 class EventLogging {
-
-	/**
-	 * @param string $streamName
-	 * @param array $event
-	 */
 	public static function submit( string $streamName, array $event ): void {
 	}
 }
diff --git a/.phpcs.xml b/.phpcs.xml
index 68595d3e..5b40bf4c 100644
--- a/.phpcs.xml
+++ b/.phpcs.xml
@@ -3,6 +3,22 @@
 	<rule ref="./vendor/mediawiki/mediawiki-codesniffer/MediaWiki">
 		<exclude name="MediaWiki.WhiteSpace.SpaceBeforeSingleLineComment.NewLineComment" />
 	</rule>
+
+	<rule ref="MediaWiki.Commenting.ClassLevelLicense">
+		<properties>
+			<property name="license" value="GPL-2.0-or-later" />
+		</properties>
+	</rule>
+	<rule ref="Squiz.Strings.DoubleQuoteUsage">
+		<exclude name="Squiz.Strings.DoubleQuoteUsage.ContainsVar" />
+	</rule>
+	<rule ref="Squiz.WhiteSpace.FunctionSpacing.AfterLast">
+		<severity>5</severity>
+	</rule>
+	<rule ref="Squiz.WhiteSpace.FunctionSpacing.BeforeFirst">
+		<severity>5</severity>
+	</rule>
+
 	<file>.</file>
 	<arg name="extensions" value="php" />
 	<arg name="encoding" value="UTF-8" />
diff --git a/includes/Api/ApiTemplateData.php b/includes/Api/ApiTemplateData.php
index c224213a..12f520f3 100644
--- a/includes/Api/ApiTemplateData.php
+++ b/includes/Api/ApiTemplateData.php
@@ -1,10 +1,4 @@
 <?php
-/**
- * Implement the 'templatedata' query module in the API.
- * Format JSON only.
- *
- * @file
- */
 
 namespace MediaWiki\Extension\TemplateData\Api;
 
@@ -21,16 +15,16 @@ use TextContent;
 use Wikimedia\ParamValidator\ParamValidator;
 
 /**
+ * Implement the 'templatedata' query module in the API.
+ * Format JSON only.
+ * @license GPL-2.0-or-later
  * @ingroup API
  * @emits error.code templatedata-corrupt
  * @todo Support continuation (see I1a6e51cd)
  */
 class ApiTemplateData extends ApiBase {
 
-	/**
-	 * @var ApiPageSet|null
-	 */
-	private $mPageSet = null;
+	private ?ApiPageSet $mPageSet = null;
 
 	/**
 	 * For backwards compatibility, this module needs to output format=json when
@@ -47,9 +41,6 @@ class ApiTemplateData extends ApiBase {
 		return null;
 	}
 
-	/**
-	 * @return ApiPageSet
-	 */
 	private function getPageSet(): ApiPageSet {
 		$this->mPageSet ??= new ApiPageSet( $this );
 		return $this->mPageSet;
@@ -281,4 +272,5 @@ class ApiTemplateData extends ApiBase {
 	public function getHelpUrls() {
 		return 'https://www.mediawiki.org/wiki/Special:MyLanguage/Extension:TemplateData';
 	}
+
 }
diff --git a/includes/Hooks.php b/includes/Hooks.php
index eb681fd1..d16ca180 100644
--- a/includes/Hooks.php
+++ b/includes/Hooks.php
@@ -1,7 +1,5 @@
 <?php
 
-// phpcs:disable MediaWiki.NamingConventions.LowerCamelFunctionsName.FunctionName
-
 namespace MediaWiki\Extension\TemplateData;
 
 use CommentStoreComment;
@@ -30,12 +28,9 @@ use ResourceLoader;
 use Status;
 
 /**
- * Hooks for TemplateData extension
- *
- * @file
- * @ingroup Extensions
+ * @license GPL-2.0-or-later
+ * phpcs:disable MediaWiki.NamingConventions.LowerCamelFunctionsName
  */
-
 class Hooks implements
 	EditPage__showEditForm_fieldsHook,
 	ParserFirstCallInitHook,
@@ -126,16 +121,11 @@ class Hooks implements
 		return true;
 	}
 
-	/**
-	 * @param RevisionRecord $revisionRecord
-	 * @param ?string $newPageProperty
-	 * @param UserIdentity $user
-	 */
 	private static function logChangeEvent(
 		RevisionRecord $revisionRecord,
 		?string $newPageProperty,
 		UserIdentity $user
-	) {
+	): void {
 		if ( !ExtensionRegistry::getInstance()->isLoaded( 'EventLogging' ) ) {
 			return;
 		}
@@ -213,7 +203,7 @@ class Hooks implements
 	 *
 	 * @return string HTML to insert in the page.
 	 */
-	public static function render( $input, $args, Parser $parser, $frame ) {
+	public static function render( ?string $input, array $args, Parser $parser, PPFrame $frame ): string {
 		$parserOutput = $parser->getOutput();
 		$ti = TemplateDataBlob::newFromJSON( wfGetDB( DB_REPLICA ), $input ?? '' );
 
@@ -268,7 +258,6 @@ class Hooks implements
 			$localizer = new TemplateDataMessageLocalizer( $lang );
 			$formatter = new TemplateDataHtmlFormatter( $localizer, $lang->getCode() );
 			$formatter->replaceEditLink( $text );
-
 		}
 	}
 
@@ -315,7 +304,7 @@ class Hooks implements
 			}
 
 			if ( !$title->exists() ) {
-				$tplData[$tplTitle] = (object)[ "missing" => true ];
+				$tplData[$tplTitle] = (object)[ 'missing' => true ];
 				continue;
 			}
 
@@ -331,7 +320,7 @@ class Hooks implements
 			$props = $pageProps->getProperties( $title, 'templatedata' );
 			if ( !isset( $props[$pageId] ) ) {
 				// No templatedata
-				$tplData[$tplTitle] = (object)[ "notemplatedata" => true ];
+				$tplData[$tplTitle] = (object)[ 'notemplatedata' => true ];
 				continue;
 			}
 
@@ -339,7 +328,7 @@ class Hooks implements
 			$status = $tdb->getStatus();
 			if ( !$status->isOK() ) {
 				// Invalid data. Parsoid has no use for the error.
-				$tplData[$tplTitle] = (object)[ "notemplatedata" => true ];
+				$tplData[$tplTitle] = (object)[ 'notemplatedata' => true ];
 				continue;
 			}
 
diff --git a/includes/TemplateDataBlob.php b/includes/TemplateDataBlob.php
index 4dac071a..7b6dfa4d 100644
--- a/includes/TemplateDataBlob.php
+++ b/includes/TemplateDataBlob.php
@@ -1,8 +1,4 @@
 <?php
-/**
- * @file
- * @ingroup Extensions
- */
 
 namespace MediaWiki\Extension\TemplateData;
 
@@ -15,18 +11,12 @@ use Wikimedia\Rdbms\IReadableDatabase;
  * Represents the information about a template,
  * coming from the JSON blob in the <templatedata> tags
  * on wiki pages.
+ * @license GPL-2.0-or-later
  */
 class TemplateDataBlob {
 
-	/**
-	 * @var string
-	 */
-	protected $json;
-
-	/**
-	 * @var Status
-	 */
-	protected $status;
+	protected string $json;
+	protected Status $status;
 
 	/**
 	 * Parse and validate passed JSON and create a blob handling
@@ -117,9 +107,6 @@ class TemplateDataBlob {
 		return null;
 	}
 
-	/**
-	 * @return Status
-	 */
 	public function getStatus(): Status {
 		return $this->status;
 	}
diff --git a/includes/TemplateDataCompressedBlob.php b/includes/TemplateDataCompressedBlob.php
index 13febd1d..a803320c 100644
--- a/includes/TemplateDataCompressedBlob.php
+++ b/includes/TemplateDataCompressedBlob.php
@@ -1,8 +1,4 @@
 <?php
-/**
- * @file
- * @ingroup Extensions
- */
 
 namespace MediaWiki\Extension\TemplateData;
 
@@ -14,15 +10,17 @@ use Message;
  * on wiki pages.
  * This implementation stores the information as a compressed gzip blob
  * in the database.
+ * @license GPL-2.0-or-later
  */
 class TemplateDataCompressedBlob extends TemplateDataBlob {
+
 	// Size of MySQL 'blob' field; page_props table where the data is stored uses one.
 	private const MAX_LENGTH = 65535;
 
 	/**
 	 * @var string In-object cache for {@see getJSONForDatabase}
 	 */
-	private $jsonDB;
+	private string $jsonDB;
 
 	/**
 	 * @inheritDoc
diff --git a/includes/TemplateDataHtmlFormatter.php b/includes/TemplateDataHtmlFormatter.php
index 99bd5a0e..db65e691 100644
--- a/includes/TemplateDataHtmlFormatter.php
+++ b/includes/TemplateDataHtmlFormatter.php
@@ -9,18 +9,14 @@ use MediaWiki\Title\Title;
 use MessageLocalizer;
 use stdClass;
 
+/**
+ * @license GPL-2.0-or-later
+ */
 class TemplateDataHtmlFormatter {
 
-	/** @var MessageLocalizer */
-	private $localizer;
+	private MessageLocalizer $localizer;
+	private string $languageCode;
 
-	/** @var string */
-	private $languageCode;
-
-	/**
-	 * @param MessageLocalizer $localizer
-	 * @param string $languageCode
-	 */
 	public function __construct( MessageLocalizer $localizer, string $languageCode = 'en' ) {
 		$this->localizer = $localizer;
 		$this->languageCode = $languageCode;
@@ -57,7 +53,7 @@ class TemplateDataHtmlFormatter {
 			}
 		}
 
-		$sorting = count( (array)$data->params ) > 1 ? " sortable" : "";
+		$sorting = count( (array)$data->params ) > 1 ? ' sortable' : '';
 		$html = '<header>'
 			. Html::element( 'p',
 				[
@@ -138,12 +134,12 @@ class TemplateDataHtmlFormatter {
 	 *
 	 * @param string &$text
 	 */
-	public function replaceEditLink( string &$text ) {
+	public function replaceEditLink( string &$text ): void {
 		$localizer = $this->localizer;
 		$text = preg_replace_callback(
 			// Based on EDITSECTION_REGEX in ParserOutput
 			'#<mw:edittemplatedata page="(.*?)"></mw:edittemplatedata>#s',
-			static function ( $m ) use ( $localizer ) {
+			static function ( array $m ) use ( $localizer ): string {
 				$editsectionPage = Title::newFromText( htmlspecialchars_decode( $m[1] ) );
 
 				if ( !is_object( $editsectionPage ) ) {
diff --git a/includes/TemplateDataMessageLocalizer.php b/includes/TemplateDataMessageLocalizer.php
index 2398b480..ce347ba8 100644
--- a/includes/TemplateDataMessageLocalizer.php
+++ b/includes/TemplateDataMessageLocalizer.php
@@ -6,16 +6,13 @@ use Language;
 use MessageLocalizer;
 
 /**
+ * @license GPL-2.0-or-later
  * @codeCoverageIgnore Trivial facade
  */
 class TemplateDataMessageLocalizer implements MessageLocalizer {
 
-	/** @var Language */
-	private $language;
+	private Language $language;
 
-	/**
-	 * @param Language $language
-	 */
 	public function __construct( Language $language ) {
 		$this->language = $language;
 	}
diff --git a/includes/TemplateDataNormalizer.php b/includes/TemplateDataNormalizer.php
index 1e22f139..00fb912c 100644
--- a/includes/TemplateDataNormalizer.php
+++ b/includes/TemplateDataNormalizer.php
@@ -4,6 +4,9 @@ namespace MediaWiki\Extension\TemplateData;
 
 use stdClass;
 
+/**
+ * @license GPL-2.0-or-later
+ */
 class TemplateDataNormalizer {
 
 	public const DEPRECATED_PARAMETER_TYPES = [
@@ -13,12 +16,8 @@ class TemplateDataNormalizer {
 		'string/wiki-file-name' => 'wiki-file-name',
 	];
 
-	/** @var string */
 	private string $contentLanguageCode;
 
-	/**
-	 * @param string $contentLanguageCode
-	 */
 	public function __construct( string $contentLanguageCode ) {
 		$this->contentLanguageCode = $contentLanguageCode;
 	}
@@ -26,7 +25,7 @@ class TemplateDataNormalizer {
 	/**
 	 * @param stdClass $data Expected to be valid according to the {@see TemplateDataValidator}
 	 */
-	public function normalize( stdClass $data ) {
+	public function normalize( stdClass $data ): void {
 		$data->description ??= null;
 		$data->sets ??= [];
 		$data->maps ??= (object)[];
@@ -55,10 +54,7 @@ class TemplateDataNormalizer {
 		}
 	}
 
-	/**
-	 * @param stdClass $paramObj
-	 */
-	private function normalizeParameter( stdClass $paramObj ) {
+	private function normalizeParameter( stdClass $paramObj ): void {
 		$paramObj->label ??= null;
 		$paramObj->description ??= null;
 		$paramObj->required ??= false;
@@ -91,7 +87,7 @@ class TemplateDataNormalizer {
 	/**
 	 * @param string|stdClass &$text
 	 */
-	private function normaliseInterfaceText( &$text ) {
+	private function normaliseInterfaceText( &$text ): void {
 		if ( is_string( $text ) ) {
 			$text = (object)[ $this->contentLanguageCode => $text ];
 		}
diff --git a/includes/TemplateDataStatus.php b/includes/TemplateDataStatus.php
index bc9c9587..19d55a68 100644
--- a/includes/TemplateDataStatus.php
+++ b/includes/TemplateDataStatus.php
@@ -4,6 +4,9 @@ namespace MediaWiki\Extension\TemplateData;
 
 use Status;
 
+/**
+ * @license GPL-2.0-or-later
+ */
 class TemplateDataStatus {
 
 	/**
diff --git a/includes/TemplateDataValidator.php b/includes/TemplateDataValidator.php
index 81be41f9..69b0cee4 100644
--- a/includes/TemplateDataValidator.php
+++ b/includes/TemplateDataValidator.php
@@ -5,6 +5,9 @@ namespace MediaWiki\Extension\TemplateData;
 use Status;
 use stdClass;
 
+/**
+ * @license GPL-2.0-or-later
+ */
 class TemplateDataValidator {
 
 	public const PREDEFINED_FORMATS = [
@@ -53,7 +56,7 @@ class TemplateDataValidator {
 	];
 
 	/** @var string[] */
-	private $validParameterTypes;
+	private array $validParameterTypes;
 
 	/**
 	 * @param string[] $additionalParameterTypes
@@ -282,7 +285,7 @@ class TemplateDataValidator {
 		} elseif ( count( $paramOrder ) < count( (array)$params ) ) {
 			$missing = array_diff( array_keys( (array)$params ), $paramOrder );
 			return Status::newFatal( 'templatedata-invalid-missing',
-				"paramOrder[ \"" . implode( '", "', $missing ) . '" ]' );
+				'paramOrder[ "' . implode( '", "', $missing ) . '" ]' );
 		}
 
 		// Validate each of the values corresponds to a parameter and that there are no
@@ -413,10 +416,6 @@ class TemplateDataValidator {
 		return null;
 	}
 
-	/**
-	 * @param string|null $format
-	 * @return bool
-	 */
 	private function isValidCustomFormatString( ?string $format ): bool {
 		return $format && preg_match( '/^\n?{{ *_+\n? *\|\n? *_+ *= *_+\n? *}}\n?$/', $format );
 	}
diff --git a/maintenance/validateTemplateData.php b/maintenance/validateTemplateData.php
index 1724866b..f77c897f 100644
--- a/maintenance/validateTemplateData.php
+++ b/maintenance/validateTemplateData.php
@@ -9,6 +9,9 @@ require_once "$IP/maintenance/Maintenance.php";
 use MediaWiki\Extension\TemplateData\TemplateDataBlob;
 use MediaWiki\Title\Title;
 
+/**
+ * @license GPL-2.0-or-later
+ */
 class ValidateTemplateData extends Maintenance {
 
 	public function __construct() {
@@ -60,6 +63,7 @@ class ValidateTemplateData extends Maintenance {
 		$this->output( "Rows checked: {$rowsChecked}\n" );
 		$this->output( "Bad rows: {$badRows}\n" );
 	}
+
 }
 
 $maintClass = ValidateTemplateData::class;
diff --git a/tests/phpunit/SerializationTest.php b/tests/phpunit/SerializationTest.php
index 472e9b6b..ebdef632 100644
--- a/tests/phpunit/SerializationTest.php
+++ b/tests/phpunit/SerializationTest.php
@@ -3,8 +3,8 @@
 use MediaWiki\Extension\TemplateData\TemplateDataStatus;
 
 /**
- * @group TemplateData
  * @covers \MediaWiki\Extension\TemplateData\TemplateDataStatus
+ * @license GPL-2.0-or-later
  */
 class SerializationTest extends MediaWikiIntegrationTestCase {
 
diff --git a/tests/phpunit/TemplateDataBlobTest.php b/tests/phpunit/TemplateDataBlobTest.php
index a44ca1d4..58a48d20 100644
--- a/tests/phpunit/TemplateDataBlobTest.php
+++ b/tests/phpunit/TemplateDataBlobTest.php
@@ -8,12 +8,12 @@ use MediaWiki\Title\Title;
 use Wikimedia\TestingAccessWrapper;
 
 /**
- * @group TemplateData
  * @group Database
  * @covers \MediaWiki\Extension\TemplateData\TemplateDataBlob
  * @covers \MediaWiki\Extension\TemplateData\TemplateDataCompressedBlob
  * @covers \MediaWiki\Extension\TemplateData\TemplateDataNormalizer
  * @covers \MediaWiki\Extension\TemplateData\TemplateDataValidator
+ * @license GPL-2.0-or-later
  */
 class TemplateDataBlobTest extends MediaWikiIntegrationTestCase {
 
@@ -1537,9 +1537,11 @@ HTML
 	public function testGetHtml( array $data, string $expected ) {
 		$t = TemplateDataBlob::newFromJSON( $this->db, json_encode( $data ) );
 		$localizer = new class implements MessageLocalizer {
+
 			public function msg( $key, ...$params ) {
 				return new RawMessage( "($key)" );
 			}
+
 		};
 		$title = Title::newFromText( 'Template:Test/doc' );
 		$formatter = new TemplateDataHtmlFormatter( $localizer );
@@ -1550,4 +1552,5 @@ HTML
 
 		$this->assertSame( $linedExpected, $linedActual );
 	}
+
 }