How can I back up my app data?

I keep most of my personal data on a shared partition, which I back up elsewhere. But I want to back up my app data, such as Firefox settings.

I haven’t been able to set everything up in Fedora, and may need to try installing another distro, so I want to be able to retrieve my data afterwards.

Firefox stores its profiles in ~/.mozilla, a hidden directory (~ being $HOME). In Gnome’s file manager nautilus, hit CTRL+H to display hidden files.

Thunderbird stores in ~/.thunderbird.

Your configs is stored in ~/.config, and
“app data” is in ~/.local/share.

So, you backup of your home directory contains all you need to setup the same system with configs, profiles, and app data again.

Edit: if you want to find out more about what’s supposed to stored where, read XDG Base Directory Specification