Interesting men's shirt picture

This picture is from the University of Heildelberg's codex for Pontus and Sidonia, this scene is entitled Potus trades his clothes with a Begger.

Cod. Pal. germ. 142
Pontus und Sidonia
Stuttgart (?) - Werkstatt Ludwig Henfflin
um 1475
Blatt:     90r (Pontus tauscht seine Kleider mit einem Bettler)

http://digi.ub.uni-heidelberg.de/sammlung1/werk/cpg142.xml?docname=cpg142&pageid=PAGE0185

What I find interesting is the beggers shirt, which appears to have gathers at the center neck. Not a big bunch of them, just a few.