/usr/bin/glib-compile-schemas is in libglib2.0-bin 2.42.1-1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/x86_64-linux-gnu/glib-2.0/glib-compile-schemas
/usr/bin/../lib/x86_64-linux-gnu/glib-2.0/glib-compile-schemas