Integrated WM thingy aka GtkHeaderBar (?) should be optional if not running under a GNOME session
I understand that having applications draw their own integrated titlebar instead of letting the windowmanager do it is part of the HIG guidelines to ensure tight control over GNOME's session look and feel. If that's considered important, it should be considered equally important not to force an alien look on/under other desktop environments.
Epiphany is one of a very select few GNOME apps that I am interested in running (being about the only other Webkit2-based desktop browser aside Safari). However, I find it hard to stomach that there is no easy way to let it handle its window decorations by whatever application I chose to be in charge of that, be it KWin, xfwm4 or quartz-wm.
A quick look at the code suggests that this choice isn't imposed by a GNOME library but is instead implemented in multiple locations using GtkHeaderBar instances. (I'm not a GTk developer so this surprises me, but also discourages me from trying to come up with a patch...)
Would it be technically possible (and politically conceivable...) to make the use of these widgets optional, at least when not running under a GNOME session (a bit like how the gnome-control-centre requires XDG_CURRENT_DESKTOP=GNOME
in order to show any controls)?
FWIW: most if not all of the big browsers that roll their own window titlebars by default have an option to use "native windows".