You might want to file an upstream bug at https://bugzilla.mozilla.org/enter_bug.cgi#h=dupes%7CFirefox to request the old behaviour back, or at least ask for a console warning when using the "-private" flag together with a URL, or when there's already a running instance.
If you do please link it here, for future reference. Thanks! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1835650 Title: firefox fails to open private sessions from bash To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1835650/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs