$ git clone -n https://src.fedoraproject.org/rpms/rust-byte-unit3.git /var/lib/mock/f42-build-3282733-41399/root/chroot_tmpdir/scmroot/rust-byte-unit3
Cloning into '/var/lib/mock/f42-build-3282733-41399/root/chroot_tmpdir/scmroot/rust-byte-unit3'...
$ git fetch origin c1cd03d765c6b550c2e1d1ff1666d59cac8819de:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-byte-unit3
 * [new ref]         c1cd03d765c6b550c2e1d1ff1666d59cac8819de -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c1cd03d compat package no longer needed