$ git clone -n https://src.fedoraproject.org/rpms/golang-x-image.git /var/lib/mock/f39-build-1541430-36491/root/chroot_tmpdir/scmroot/golang-x-image
Cloning into '/var/lib/mock/f39-build-1541430-36491/root/chroot_tmpdir/scmroot/golang-x-image'...
$ git fetch origin 88023f3430c4956d2696371c4c15143d7d8f75e7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-x-image
 * [new ref]         88023f3430c4956d2696371c4c15143d7d8f75e7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 88023f3 Update to 0.13.0