fyi, just tried to add a new addon to my 2 systems using legacy Mozilla addon Discovery and it failed to list any addons.
So, I decided to switch my development system to the new webthingsio image. After pulling the new webthingsio/gateway docker image it started up ok, and more importantly, addon Discovery once again worked.
Did not attempt to restart either of my mozilla docker images to see if that corrected legacy mozilla addon Discovery.
For me, I don’t care as I’m now running webthingsio which is probably the correct thing for others to do too…