$ git clone -n https://src.fedoraproject.org/rpms/mingw-gtkmm30.git /var/lib/mock/f39-build-1842118-42002/root/chroot_tmpdir/scmroot/mingw-gtkmm30
Cloning into '/var/lib/mock/f39-build-1842118-42002/root/chroot_tmpdir/scmroot/mingw-gtkmm30'...
$ git fetch origin 91bdf9a475bacbde9eda55646c93c90d2f5fde7a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mingw-gtkmm30
 * [new ref]         91bdf9a475bacbde9eda55646c93c90d2f5fde7a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 91bdf9a Update to 3.24.8