$ git clone -n https://src.fedoraproject.org/rpms/kf6-knewstuff.git /var/lib/mock/f42-build-862124-170665/root/chroot_tmpdir/scmroot/kf6-knewstuff
Cloning into '/var/lib/mock/f42-build-862124-170665/root/chroot_tmpdir/scmroot/kf6-knewstuff'...
$ git fetch origin f748df87334d1ec886633185888b41b400cf861a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-knewstuff
 * [new ref]         f748df87334d1ec886633185888b41b400cf861a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f748df8 6.8.0