$ git clone -n https://src.fedoraproject.org/rpms/rust-byte-unit.git /var/lib/mock/f40-build-2650880-66878/root/chroot_tmpdir/scmroot/rust-byte-unit
Cloning into '/var/lib/mock/f40-build-2650880-66878/root/chroot_tmpdir/scmroot/rust-byte-unit'...
$ git fetch origin 8c40f10ecd7c80f993ecef488aa2512954eef074:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-byte-unit
 * [new ref]         8c40f10ecd7c80f993ecef488aa2512954eef074 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8c40f10 Update to 5.1.4 (rhbz#2251469)