This may be an use case although I havent verified that. Also, TB comes with a web view used for SSO logins for instance but which can be used just like a browser. There, UB definitely makes sense
I have multiple email accounts and the "Correct Identity" plugin is useful for setting rules to ensure I use the correct account for different recipients.
Does this help block or ID email pixels (email tracking pixels or beacons)? I’ve not seen this being done on Thunderbird as an add-on...though I’ve seen firewalls (in the past) able to selectively block specific connections.
I would be more comfortable with an alternative to adguard given it's origins. I dont use any of their dns or vpn services though, only ios safari content blocker, but still.