The smallest download you can do is cloning with depth 1 (around 840 MB):

$ git clone --depth 1 https://github.com/xerxes2/gecko-dev.git

$ cp mozconfig.proto mozconfig
$ ./mach configure
$ ./mach build

And start it with:

$ ./mach run

This port is using the widget/gtk4 directory exclusively and outside of it you must use "#ifdef MOZ_GTK4". It's focused on Wayland so X11 is disabled, for now at least. All code must be fully compatible with the official Mozilla GTK3 port.

All contributions very much welcome.

1. Make it build (done)
2. Get it to start (done)
3. Make the upstart/shutdown sequences work properly (60%)
4. Fix input events
   • Keyboard (20%)
   • Pointer (20%)
   • Touch (20%)
5. Implement missing features
   • Clipboard (0%)
   • Drag-and-drop (0%)
   • Filepicker (0%)
   • Appchooser (0%)
   • Colorpicker (0%)
   • Emojipicker (0%)

Ticket at Mozilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1701123

GTK4 porting doc: https://docs.gtk.org/gtk4/migrating-3to4.html