$ git clone -n https://src.fedoraproject.org/rpms/hostname.git /var/lib/mock/f40-build-2003857-44886/root/chroot_tmpdir/scmroot/hostname
Cloning into '/var/lib/mock/f40-build-2003857-44886/root/chroot_tmpdir/scmroot/hostname'...
$ git fetch origin 88ab146871cc35bea7f38370c1a0f106bf7638a2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/hostname
 * [new ref]         88ab146871cc35bea7f38370c1a0f106bf7638a2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 88ab146 Add rpminspect waivers