$ git clone -n https://src.fedoraproject.org/rpms/rust-serial_test0.5.git /var/lib/mock/f39-build-1488970-34501/root/chroot_tmpdir/scmroot/rust-serial_test0.5
Cloning into '/var/lib/mock/f39-build-1488970-34501/root/chroot_tmpdir/scmroot/rust-serial_test0.5'...
$ git fetch origin 02849a81b1d1e3d2d4b1be0f8d4419aecf77d83b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serial_test0.5
 * [new ref]         02849a81b1d1e3d2d4b1be0f8d4419aecf77d83b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 02849a8 Regenerate with rust2rpm v24