/usr/include/GNUstep/gnustep/gui/GMAppKit.h is in libgnustep-gui-dev 0.20.0-3+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | #warning GMAppKit.h is now included using the path <GNUstepGUI/GMAppKit.h>
#include <GNUstepGUI/GMAppKit.h>
|