$ git clone -n https://src.fedoraproject.org/rpms/kf6-knewstuff.git /var/lib/mock/f42-build-side-1-3537134-46559/root/chroot_tmpdir/scmroot/kf6-knewstuff
Cloning into '/var/lib/mock/f42-build-side-1-3537134-46559/root/chroot_tmpdir/scmroot/kf6-knewstuff'...
$ git fetch origin cd378aeb558be9bd70a6e486562cc34b6b1b8bf1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-knewstuff
 * [new ref]         cd378aeb558be9bd70a6e486562cc34b6b1b8bf1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cd378ae 6.14.0