// For 404 handled thumbnails, we only use the base name of the URI
// for the thumb params and the parent directory for the source file name.
- // Check that the zone relative path matches up so squid caches won't pick
+ // Check that the zone relative path matches up so CDN caches won't pick
// up thumbs that would not be purged on source file deletion (T36231).
if ( $rel404 !== null ) { // thumbnail was handled via 404
if ( rawurldecode( $rel404 ) === $img->getThumbRel( $thumbName ) ) {