$ git clone -n https://src.fedoraproject.org/rpms/rust-routinator.git /var/lib/mock/f40-build-790904-136885/root/chroot_tmpdir/scmroot/rust-routinator
Cloning into '/var/lib/mock/f40-build-790904-136885/root/chroot_tmpdir/scmroot/rust-routinator'...
$ git fetch origin f55b9301608616e5883130464bbd17a32193f5d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-routinator
 * [new ref]         f55b9301608616e5883130464bbd17a32193f5d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f55b930 Initial package (rhbz#2259990)