$ git clone -n https://src.fedoraproject.org/rpms/rust-ff0.13.git /var/lib/mock/f45-build-41623-784/root/chroot_tmpdir/scmroot/rust-ff0.13
Cloning into '/var/lib/mock/f45-build-41623-784/root/chroot_tmpdir/scmroot/rust-ff0.13'...
$ git fetch origin 86db99388ebcef7e731c314d1d6335f210cf3f18:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-ff0.13
 * [new ref]         86db99388ebcef7e731c314d1d6335f210cf3f18 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86db993 Initial compat package