$ git clone -n https://src.fedoraproject.org/rpms/libunibreak.git /var/lib/mock/f40-build-800657-143609/root/chroot_tmpdir/scmroot/libunibreak
Cloning into '/var/lib/mock/f40-build-800657-143609/root/chroot_tmpdir/scmroot/libunibreak'...
$ git fetch origin 13e3720a748fb163c6179b48f9d6cd122b5489aa:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libunibreak
 * [new ref]         13e3720a748fb163c6179b48f9d6cd122b5489aa -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 13e3720 Update to 6.1 (RHBZ#2266204)