$ git clone -n https://src.fedoraproject.org/rpms/rust-run_script.git /var/lib/mock/f40-build-2288184-55773/root/chroot_tmpdir/scmroot/rust-run_script
Cloning into '/var/lib/mock/f40-build-2288184-55773/root/chroot_tmpdir/scmroot/rust-run_script'...
$ git fetch origin cb89dd02275a1a2e2a6f920686d0a3ace6683170:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-run_script
 * [new ref]         cb89dd02275a1a2e2a6f920686d0a3ace6683170 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cb89dd0 Initial package