can’t see most of what’s in the xpresso from that screen shot but it’s possible to tell he’s not dealing with clones but is arranging a bunch of spheres under a null along the spline and feeding the nulls into the xpresso with a Hierarchy node, without seeing what he is doing with the spheres it’s hard to know why you would want do it in xpresso rather than truly cloning along a spline ( or just Arranging along a spline)