Try more strict phpstan.neon

includes/class-site-health-test-wordpress-translations-locale.php

@@ -98,7 +98,7 @@ public function run_test() {
 			$formatted_name = Options_General::locale_name_format( $locale );
 
 			// Check if Language Packs exist for the Locale and if the Language Pack major version is the same as the WordPress installed major version.
-			if ( $locale->has_translations() && isset( $locale_translations_version ) && $translation_project_version === $locale_translations_version ) {
+			if ( $locale->has_translations() && $translation_project_version === $locale_translations_version ) {
 
 				$this->test_status = self::TRANSLATION_TOOLS_SITE_HEALTH_STATUS_GOOD;
 				$this->test_label  = sprintf(

includes/class-update-translations.php

@@ -108,6 +108,8 @@ public function update_translation( $type, $project, $wp_locale, $generate_po_mo
 				$generate_po = $this->generate_po( $destination, $project, $locale, $download['data'] );
 				array_push( $result['log'], $generate_po['log'] );
 				$result['data'] = $generate_po['data'];
+				/** @var array{log: array, data: true|WP_Error} $result Results. */
+				\PHPStan\dumpType( $result['data'] );
 				if ( is_wp_error( $result['data'] ) ) {
 					return $result;
 				}
@@ -305,7 +307,7 @@ public function download_translations( $type, $project, $locale ) {
 		 * @param Locale $locale        Locale object.
 		 * @param array  $response      HTTP response.
 		 *
-		 * @return array|WP_Error       Array on success, WP_Error on failure.
+		 * @return array{log:string, data:true}|array{data:WP_Error} Array on success, WP_Error on failure.
 		 */
 		public function generate_po( $destination, $project, $locale, $response ) {
 

phpstan.neon

@@ -15,4 +15,3 @@ parameters:
 			- assets/lib/locales/locales.php
 	# TODO Tell PHPStan what is inside arrays.
 	checkMissingIterableValueType: false
-	treatPhpDocTypesAsCertain: false