$ git clone -n https://src.fedoraproject.org/rpms/rust-bit_field.git /var/lib/mock/f38-build-side-43-rust-devel-1412150-31438/root/chroot_tmpdir/scmroot/rust-bit_field
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1412150-31438/root/chroot_tmpdir/scmroot/rust-bit_field'...
$ git fetch origin ceb38002944b52a4c0767e8eb6e6953cc1fde6ab:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bit_field
 * [new ref]         ceb38002944b52a4c0767e8eb6e6953cc1fde6ab -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ceb3800 Update to 0.10.2