diff --git a/src/infrastructure/lint/PhabricatorLintEngine.php b/src/infrastructure/lint/PhabricatorLintEngine.php
index 28fb9967e..5248891b0 100644
--- a/src/infrastructure/lint/PhabricatorLintEngine.php
+++ b/src/infrastructure/lint/PhabricatorLintEngine.php
@@ -1,52 +1,55 @@
 <?php
 
-final class PhabricatorLintEngine extends PhutilLintEngine {
+/**
+ * @concrete-extensible
+ */
+class PhabricatorLintEngine extends PhutilLintEngine {
 
   public function buildLinters() {
     $linters = parent::buildLinters();
 
     foreach ($linters as $linter) {
       if ($linter instanceof ArcanistPhutilXHPASTLinter) {
         $linter->setDeprecatedFunctions(array(
           'phutil_escape_html' =>
             'The phutil_escape_html() function is deprecated. Raw strings '.
             'passed to phutil_tag() or hsprintf() are escaped automatically.',
 
           'javelin_render_tag' =>
             'The javelin_render_tag() function is deprecated and unsafe. '.
             'Use javelin_tag() instead.',
 
           'phabricator_render_form' =>
             'The phabricator_render_form() function is deprecated and unsafe. '.
             'Use phabricator_form() instead.',
         ));
       }
     }
 
     $paths = $this->getPaths();
 
     foreach ($paths as $key => $path) {
       if (!$this->pathExists($path)) {
         unset($paths[$key]);
       }
     }
 
     $javelin_linter = new PhabricatorJavelinLinter();
     $linters[] = $javelin_linter;
 
     foreach ($paths as $path) {
       if (strpos($path, 'support/aphlict/') !== false) {
         // This stuff is Node.js, not Javelin, so don't apply the Javelin
         // linter.
         continue;
       }
       if (preg_match('/\.js$/', $path)) {
         $javelin_linter->addPath($path);
         $javelin_linter->addData($path, $this->loadData($path));
       }
     }
 
     return $linters;
   }
 
 }