Notable mention of Mozilla being a Platinum sponsor.

Fully agreed. On almost any atomic distro, /home/user is writeable like usual, so any attacker is able to persist itself by editing ~/.bashrc and putting a binary somewhere.

Yes, ~/.local/share/flatpak includes all user installed flatpaks, while /var/lib/flatpak includes all system wide installed flatpaks. Both include repository information and required runtimes (i.e. dependencies).

This does not include user data, which is stored in ~/.var/app.

Make sure to test your backup just in case on another system/VM.

It’s an annoying change for anyone using discord to share files outside of it’s closed platform but doesn’t affect most people.

I wonder whether bridges for matrix have to be fixed or if they’re already editing messages bridged to matrix to the new url.