In Scene Viewer the Basemap widget has a transparency slider that is useful for viewing features that are underground:
I cannot find the same capability in Experience Builder in either the dedicated Basemap Gallery widget or in the basemap tool that can be enabled on the map. I think this capability should be added to the Basemap Gallery widget (as a default or as a configurable option) to have some parity with the Scene Viewer and to allow underground assets to be viewed in EB.
