$ git clone -n https://src.fedoraproject.org/rpms/gtk4.git /var/lib/mock/f42-build-side-1-3586828-46926/root/chroot_tmpdir/scmroot/gtk4
Cloning into '/var/lib/mock/f42-build-side-1-3586828-46926/root/chroot_tmpdir/scmroot/gtk4'...
$ git fetch origin 8bb009fb48dc0a5e910a206202f719226318be1f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gtk4
 * [new ref]         8bb009fb48dc0a5e910a206202f719226318be1f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8bb009f Update to 4.18.6