Setting advanced default privacy and security settings
How can I change default browser settings in Firefox for Mac v. 81.0.1 (64-bit) to 1) Always start in Private Mode (and by the way, how can I tell I'm in private mode?) and 2) Always clean up by clearing all data & history without having to manually do it (it doesn't always work when you exit the browser-when I come back in, there's still cookies & site data). Thanks.
Alla svar (1)
If you are using Firefox in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History) then there is no need to clear your personal data as this is done automatically when you end the PB mode session. If you still have data from a regular session then this isn't affected and can't be removed as long as you are in PB mode and you need to start Firefox in regular mode (i.e. disable PB mode) to be able to remove this data.