$ git clone -n https://src.fedoraproject.org/rpms/kf6-knewstuff.git /var/lib/mock/f40-build-788024-134983/root/chroot_tmpdir/scmroot/kf6-knewstuff
Cloning into '/var/lib/mock/f40-build-788024-134983/root/chroot_tmpdir/scmroot/kf6-knewstuff'...
$ git fetch origin 66f1cc5b89a5b79ce5634fd7eb3828683ecbf9ea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-knewstuff
 * [new ref]         66f1cc5b89a5b79ce5634fd7eb3828683ecbf9ea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 66f1cc5 Respin: Rebuild with a new tarball before 6.0.0 release