$ git clone -n https://src.fedoraproject.org/rpms/cosmic-bg.git /var/lib/mock/f45-build-5592-340/root/chroot_tmpdir/scmroot/cosmic-bg
Cloning into '/var/lib/mock/f45-build-5592-340/root/chroot_tmpdir/scmroot/cosmic-bg'...
$ git fetch origin 17c3c142cea47953f0e61146aaffb5a6f7970f09:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cosmic-bg
 * [new ref]         17c3c142cea47953f0e61146aaffb5a6f7970f09 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 17c3c14 Update to 1.6.0