Idea: Make it easier for the user to pick an alternate file picker other than GTK's on the GNU/Linux version of Firefox
Reasoning: The GTK file picker lacks features that other file managers have, and it can be a pain to make another one to work on Firefox, to get the KDE one to work for example, you have to install xdg-desktop-portal-kde and then have to mess with the about:config settings just to get Dolphin to work with Firefox.