I am trying to de-Google my life on Ubuntu but finding Firefox and Thunderbird do no interact as I want. I tried Thunderbird to read my email and wanted to launch Firefox when I click links. First I tried [https://superuser.com/questions/1775149/open-links-from-thunderbird-with-non-default-browser this solution] this solution. Nothing changed and I never saw "choose" when I clicked the link. I still am using GMail and Chrome as default applications. I found this [https://support.mozilla.org/en-US/questions/1426739 patch to Thunderbird] patch to Thunderbird to make non-default link to Firefox browser. I find the binary at /var/lib/flatpak/app/org.mozilla.firefox/current/active/files/bin/firefox so I replaced this location in /etc/apparmor.d/usr.bin.thunderbird The links still invoke in Google Chrome The moderator on 10/8/23 replied with an even more confusing message regarding a '''''showfor''''' if Linux specific. I knew how to do it so it does not apply to me. "Note that the Linux specific information should be enclosed in a '''''showfor''''' and that you have to explain the how to do it in detail. Assume the reader has no idea how to do more than open the application." This is my first time in this forum and I am hoping I set up Firefox and Thunderbird to follow this discussion.