diff --git a/includes/LintErrorsPager.php b/includes/LintErrorsPager.php
index 3004bdea..454fed62 100644
--- a/includes/LintErrorsPager.php
+++ b/includes/LintErrorsPager.php
@@ -42,7 +42,8 @@ class LintErrorsPager extends TablePager {
 	private PermissionManager $permissionManager;
 
 	private ?string $category;
-	private ?int $categoryId;
+	/** @var mixed */
+	private $categoryId;
 	private array $namespaces;
 	private bool $exactMatch;
 	private string $title;
@@ -88,8 +89,11 @@ class LintErrorsPager extends TablePager {
 		if ( $category !== null ) {
 			$this->categoryId = $categoryManager->getCategoryId( $category );
 		} else {
-			$this->categoryId = null;
+			$this->categoryId = array_values( $this->categoryManager->getCategoryIds(
+				$this->categoryManager->getVisibleCategories()
+			) );
 		}
+
 		$this->namespaces = $namespaces;
 		$this->exactMatch = $exactMatch;
 		$this->title = $title;
@@ -109,11 +113,8 @@ class LintErrorsPager extends TablePager {
 				'linter_id', 'linter_params',
 				'linter_start', 'linter_end',
 				'linter_cat'
-			] );
-
-		if ( $this->categoryId !== null ) {
-			$queryBuilder->where( [ 'linter_cat' => $this->categoryId ] );
-		}
+			] )
+			->where( [ 'linter_cat' => $this->categoryId ] );
 
 		if ( $this->title !== '' ) {
 			$namespaces = $this->namespaces ?: [ NS_MAIN ];
@@ -184,7 +185,8 @@ class LintErrorsPager extends TablePager {
 		// category is set each time based on the category set in the lint error $row
 		// not by the class when lints are being reported by type for many pages
 		$category = $this->category;
-		if ( $category === null && $row->linter_cat !== null ) {
+		if ( $category === null ) {
+			// Assert $row->linter_cat !== null ?
 			$category = $this->categoryManager->getCategoryName( $row->linter_cat );
 		} else {
 			$row->linter_cat = $this->categoryId;
diff --git a/includes/SpecialLintErrors.php b/includes/SpecialLintErrors.php
index 9c650363..e3acdd9a 100644
--- a/includes/SpecialLintErrors.php
+++ b/includes/SpecialLintErrors.php
@@ -222,16 +222,16 @@ class SpecialLintErrors extends SpecialPage {
 	}
 
 	/**
-	 * @param string|null $par
+	 * @param string|null $subPage
 	 */
-	public function execute( $par ) {
+	public function execute( $subPage ) {
 		$request = $this->getRequest();
 		$out = $this->getOutput();
 
 		$params = $request->getQueryValues();
 
 		$this->setHeaders();
-		$this->outputHeader( $par || isset( $params[ 'titlesearch' ] ) ? 'disable-summary' : '' );
+		$this->outputHeader( $subPage || isset( $params[ 'titlesearch' ] ) ? 'disable-summary' : '' );
 
 		$namespaces = $this->findNamespaces( $request );
 
@@ -248,7 +248,7 @@ class SpecialLintErrors extends SpecialPage {
 		// of a custom namespace (just the text before a ':') to search for and pressed the associated Submit button.
 		// Added the pageback parameter to inform the code that the '<- Special:LintErrors' link had been used to allow
 		// the UI to redisplay with previous form values, instead of just resubmitting the query.
-		if ( $par === null && isset( $params[ 'titlesearch' ] ) && !isset( $params[ 'pageback'] ) ) {
+		if ( $subPage === null && isset( $params[ 'titlesearch' ] ) && !isset( $params[ 'pageback'] ) ) {
 			unset( $params[ 'title' ] );
 			$params = array_merge( [ 'pageback' => true ], $params );
 			$out->addBacklinkSubtitle( $this->getPageTitle(), $params );
@@ -276,8 +276,11 @@ class SpecialLintErrors extends SpecialPage {
 			return;
 		}
 
-		if ( in_array( $par, $this->getSubpagesForPrefixSearch() ) ) {
-			$this->category = $par;
+		if ( in_array( $subPage, array_merge(
+			$this->categoryManager->getVisibleCategories(),
+			$this->categoryManager->getInvisibleCategories()
+		) ) ) {
+			$this->category = $subPage;
 		}
 
 		if ( !$this->category ) {