$ git clone -n https://src.fedoraproject.org/rpms/system-rules.git /var/lib/mock/f40-build-2533628-61847/root/chroot_tmpdir/scmroot/system-rules
Cloning into '/var/lib/mock/f40-build-2533628-61847/root/chroot_tmpdir/scmroot/system-rules'...
$ git fetch origin 35e90545d201da71d7d802e05631722ce6560df5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/system-rules
 * [new ref]         35e90545d201da71d7d802e05631722ce6560df5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 35e9054 Rebuilt for java-21-openjdk as system jdk