$ git clone -n https://src.fedoraproject.org/rpms/glib2.git /var/lib/mock/f40-build-786639-134473/root/chroot_tmpdir/scmroot/glib2
Cloning into '/var/lib/mock/f40-build-786639-134473/root/chroot_tmpdir/scmroot/glib2'...
$ git fetch origin 201ea236920c2df4224879d86e14f141c26107cf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/glib2
 * [new ref]         201ea236920c2df4224879d86e14f141c26107cf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 201ea23 Update to 2.79.1