firefox tries to access system's snapd profile
(I accepted the offered restart to upgrade TB 8.0a10 and it didn't come up from alone again, but this is an aside since 8.5a1 works well after.)
When i logged in to trac, firefox tried to access a local snap profile and failed. I would not expect it to do that:
(/path/to/tor-browser8.0a10/Browser/firefox.real:20293): dconf-WARNING **: 23:01:32.166: Unable to open /var/lib/snapd/desktop/dconf/profile/user: Permission denied