$ git clone -n https://src.fedoraproject.org/rpms/postgresql-jdbc.git /var/lib/mock/f40-build-2255889-54266/root/chroot_tmpdir/scmroot/postgresql-jdbc
Cloning into '/var/lib/mock/f40-build-2255889-54266/root/chroot_tmpdir/scmroot/postgresql-jdbc'...
$ git fetch origin f1cecd993567f00bc7ce8d028ac88b240156abc5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/postgresql-jdbc
 * [new ref]         f1cecd993567f00bc7ce8d028ac88b240156abc5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f1cecd9 rebase to upstream version 42.7.1