diff --git a/lib/oembedhelper.php b/lib/oembedhelper.php
index 4aae815918..6d8064e660 100644
--- a/lib/oembedhelper.php
+++ b/lib/oembedhelper.php
@@ -131,6 +131,7 @@ class oEmbedHelper
         }
 
         if (empty($api)) {
+            // TRANS: Server exception thrown in oEmbed action if no API endpoint is available.
             throw new ServerException(_('No oEmbed API endpoint available.'));
         }