On my system, I wanted Firefox profiles to feel like their own browser instances. Meaning, their own app icons and to not be grouped together. Almost like how it is on MacOS.
To do this, I had to make multiple .desktop files. Here are the contents of that file. This targets flatpak, but it should work for traditional Firefox installs too.
I called this profile "Personal". Note that this says --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal". In this, "personal" is a symlink to the real profile folder name located in the same directory.
[Desktop Entry]
Version=1.0
Type=Application
Exec=/usr/bin/flatpak run --env=MOZ_APP_REMOTINGNAME=Personal --branch=stable --arch=x86_64 --command=firefox --file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal --class org.mozilla.firefox.Personal @@u %u @@
Terminal=false
X-MultipleArgs=false
Icon=/home/USERNAME/.local/share/icons/firefox-heart.png
StartupWMClass=org.mozilla.firefox.Personal
DBusActivatable=false
Categories=GNOME;GTK;Network;WebBrowser;
MimeType=application/json;application/pdf;application/rdf+xml;application/rss+xml;application/x-xpinstall;application/xhtml+xml;application/xml;audio/flac;audio/ogg;audio/webm;image/avif;image/gif;image/jpeg;image/png;image/svg+xml;image/webp;text/html;text/xml;video/ogg;video/webm;x-scheme-handler/chrome;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/mailto;
StartupNotify=true
Actions=new-window;new-private-window;
Name=Firefox (Personal)
Comment=Fast and private browser
GenericName=Web Browser
Keywords=Internet;WWW;Browser;Web;Explorer;
X-GNOME-FullName=Mozilla Firefox
[Desktop Action new-window]
Exec=/usr/bin/flatpak run --env=MOZ_APP_REMOTINGNAME=Personal --branch=stable --arch=x86_64 --command=firefox --file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal --class org.mozilla.firefox.Personal --new-window @@u %u @@
Name=New Window
[Desktop Action new-private-window]
Exec=/usr/bin/flatpak run --env=MOZ_APP_REMOTINGNAME=Personal --branch=stable --arch=x86_64 --command=firefox --file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal --class org.mozilla.firefox.Personal --private-window @@u %u @@
Name=New Private Window
firefox --profilemanager
I had a couple of problems with the profile manager.
For one, there's now two profile managers that do not work together. You can't use an old profile in the new profile manager or vice versa. You can access the old one via .desktop entry or from the CLI. But you can't access the new one from the CLI.
It's also a bit buggy. For example, if I have my "Personal" profile open and middle click the Firefox icon, it will open up another "Personal" window rather than show the profile manager. And to access the new profile manager, I first have to aim for a tiny target (especially tiny on my 100% scaled 4K monitor) and do 3 clicks. With my solution, I explicitly choose which profile to use from my dock.
It's also hit or miss on which window a link from an app will open up in. Whereas with my solution, I can set "Firefox (Personal)" as my default browser and always have stuff open there.
the custom shortcuts are so you can skip the profile manager when launching a browser window.
You can launch Firefox directly with one profile. You can also have a .desktop per profile. The problem is that the DE is probably going to group the windows together in the taskbar.
Been doing this for years with KDE. No grouping there.