$ git clone -n https://src.fedoraproject.org/rpms/rust-polyval0.6.git /var/lib/mock/f45-build-43950-809/root/chroot_tmpdir/scmroot/rust-polyval0.6
Cloning into '/var/lib/mock/f45-build-43950-809/root/chroot_tmpdir/scmroot/rust-polyval0.6'...
$ git fetch origin a064e5b010036193cb1af142b9ec1e20a87f7f96:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-polyval0.6
 * [new ref]         a064e5b010036193cb1af142b9ec1e20a87f7f96 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a064e5b Initial compat package