Use l10n on this string as well

core/templates/exception.php

@@ -3,7 +3,7 @@
 	/** @var OC_L10N $l */
 ?>
 <span class="error error-wide">
-	<h2><strong><?php p('Internal Server Error') ?></strong></h2>
+	<h2><strong><?php p($l->t('Internal Server Error')) ?></strong></h2>
 		<p><?php p($l->t('The server encountered an internal error and was unable to complete your request.')) ?></p>
 		<p><?php p($l->t('Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.')) ?></p>
 		<p><?php p($l->t('More details can be found in the server log.')) ?></p>