diff --git a/src/ol/source/IIIF.js b/src/ol/source/IIIF.js
index e165db78bb..1518da994d 100644
--- a/src/ol/source/IIIF.js
+++ b/src/ol/source/IIIF.js
@@ -56,6 +56,10 @@ function formatPercentage(percentage) {
  */
 class IIIF extends TileImage {
 
+  /**
+   * @param {Options} opt_options
+   * @api
+   */
   constructor(opt_options) {
 
     const options = opt_options || {};