Not sure where it was best to post this, but I also created a Phabricator task: https://phabricator.wikimedia.org/T268807
All the configuration required for the extension has been done, but interacting with 3D models seems to not be possible via MediaViewer. I'm not sure what the cause of this could be or how to debug? Expected behaviour: https://test.wikipedia.org/wiki/File:Programmatically_created_crystal.stl#/media/File:Programmatically_created_crystal.stl Behaviour: https://funkey.miraheze.org/wiki/File:FunKey_Button_Cover_3D_Model.STL