$ git clone -n https://src.fedoraproject.org/rpms/cheese.git /var/lib/mock/f39-build-1531015-36201/root/chroot_tmpdir/scmroot/cheese
Cloning into '/var/lib/mock/f39-build-1531015-36201/root/chroot_tmpdir/scmroot/cheese'...
$ git fetch origin 2a2d1bcdb1786ba1d568d2cbadfcaac2cf3b7540:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cheese
 * [new ref]         2a2d1bcdb1786ba1d568d2cbadfcaac2cf3b7540 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2a2d1bc Update to 44.1