/usr/share/vala-0.40/vapi/gtk+-3.0.deps is in valac-0.40-vapi 0.40.4-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7
gio-2.0 atk cairo gdk-pixbuf-2.0 gdk-3.0 pango x11