The Sling Resource Merger and the related methods can only be used with
Granite. This means that creating an overlay with a skeleton structure
is only appropriate for the standard, touch-enabled UI.Overlays for
other areas (including the classic UI) involve copying the appropriate
node and entire sub-structure, then making the required changes. Refer:
https://experienceleague.adobe.com/docs/experience-manager-65/developing/platform/overlays.html?lang=en