Belyaev was correct that selection on tameness alone leads to the emergence of traits in the domestication syndrome. In less than a decade, some of the domesticated foxes had floppy ears and curly tails (Fig. 2).
Over the course of the experiment, researchers also found the domesticated foxes displayed mottled “mutt-like” fur patterns, and they had more juvenilized facial features (shorter, rounder, more dog-like snouts) and body shapes (chunkier, rather than gracile limbs) (Fig. 3).
I think baby-like facial features are just a part of the domestication syndrome. There has been this long-going domestication experiment with silver foxes that could show that when only selected for tameness the foxes still expressed most of the traits found in other domesticated animals, too.