At some point my preferred browser got out of sync. By this I mean I installed
Chrome unstable and Firefox, and different apps would open different browsers.
Clicking on a link in the terminal would open Firefox even though (stable)
Chrome was my preferred browser.
After a little digging I found this
on the Ubuntu bug tracker and it helped sort out my preferences.
I also noticed that Firefox had taken over text/xml and that Chrome was set to
open image/webp so I fixed those too. This is all a bit of a PITA, and
counter-intuitive to how preferred apps should work. I should set them in one
place and all apps should read from that source.
Anyway, hope this helps.
Turns out Firefox kept hold of certain things, so I uninstalled it. Didn’t use
it much anyway.