$ git clone -n https://src.fedoraproject.org/rpms/FlightGear-data.git /var/lib/mock/f38-build-side-42-init-devel-565652-25895/root/chroot_tmpdir/scmroot/FlightGear-data
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-565652-25895/root/chroot_tmpdir/scmroot/FlightGear-data'...
$ git fetch origin fe2c837aad6f8630a5016bcc39d094c4b76671dd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/FlightGear-data
 * [new ref]         fe2c837aad6f8630a5016bcc39d094c4b76671dd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe2c837 new upstream release