$ git clone -n https://src.fedoraproject.org/rpms/glib2.git /var/lib/mock/f42-build-3426250-45168/root/chroot_tmpdir/scmroot/glib2
Cloning into '/var/lib/mock/f42-build-3426250-45168/root/chroot_tmpdir/scmroot/glib2'...
$ git fetch origin 0e44a4e00a29dc9f848e7bf79a651a8798f7ad0a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/glib2
 * [new ref]         0e44a4e00a29dc9f848e7bf79a651a8798f7ad0a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0e44a4e Update to 2.84.0