$ git clone -n https://src.fedoraproject.org/rpms/mailman3-fedmsg-plugin-schemas.git /var/lib/mock/f45-build-17954-506/root/chroot_tmpdir/scmroot/mailman3-fedmsg-plugin-schemas
Cloning into '/var/lib/mock/f45-build-17954-506/root/chroot_tmpdir/scmroot/mailman3-fedmsg-plugin-schemas'...
$ git fetch origin a6053d68941f684c7578005ed2ba15e81e2355cd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mailman3-fedmsg-plugin-schemas
 * [new ref]         a6053d68941f684c7578005ed2ba15e81e2355cd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a6053d6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild