$ git clone -n https://src.fedoraproject.org/rpms/kf6-purpose.git /var/lib/mock/f40-build-788031-134983/root/chroot_tmpdir/scmroot/kf6-purpose
Cloning into '/var/lib/mock/f40-build-788031-134983/root/chroot_tmpdir/scmroot/kf6-purpose'...
$ git fetch origin 8573a750b90da5519575a75f7aa74947b4b2e6c8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-purpose
 * [new ref]         8573a750b90da5519575a75f7aa74947b4b2e6c8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8573a75 6.0.0