$ git clone -n https://src.fedoraproject.org/rpms/golang-x-sys.git /var/lib/mock/f39-build-1503917-34992/root/chroot_tmpdir/scmroot/golang-x-sys
Cloning into '/var/lib/mock/f39-build-1503917-34992/root/chroot_tmpdir/scmroot/golang-x-sys'...
$ git fetch origin 88e6c0b1cad578a9ba10d2757154199d72301a91:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-x-sys
 * [new ref]         88e6c0b1cad578a9ba10d2757154199d72301a91 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 88e6c0b Update to 0.10.0