$ git clone -n https://src.fedoraproject.org/rpms/kf5-knewstuff.git /var/lib/mock/f40-build-787325-134746/root/chroot_tmpdir/scmroot/kf5-knewstuff
Cloning into '/var/lib/mock/f40-build-787325-134746/root/chroot_tmpdir/scmroot/kf5-knewstuff'...
$ git fetch origin 8de58257e64ca94e8f13b9be2d4ea7a2066e25a8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf5-knewstuff
 * [new ref]         8de58257e64ca94e8f13b9be2d4ea7a2066e25a8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8de5825 5.115.0