If you are developing apps for GNOME, I kindly ask you to pay attention to the following three key points of application usability. These are features that all GNOME GUI apps should support no matter what. In the humble opinion of this author, of course.
CTRL+Qis the primary mechanism to quit your app. Not
ALT+F4, please, that’s a Windows thing, and a carpal-tunnel syndrome -inducing keystroke at best.
F11must toggle the application back and forth from full screen mode.
CTRL+Mshould minimize the app.
And that’s it. You can map the rest of the keyboard any way you want, but please pay attention to these three items. The good thing is that many, if not most apps do support these keyboard shortcuts off-the-box.