Clarification re: "Interior holes must not touch other holes, nor touch the polyline boundary"

[JohanAR]

Does this requirement imply that two holes can't have a common point, or does it just mean that a point belonging to one hole can't lie on the edge of another hole?

Same question for hole/polyline: Does it apply to point/point sharing, or only point/line overlap? I.e. can a hole share a point with the polyline boundary?

Found an illustration that is very similar to what I'm trying to say: https://i.stack.imgur.com/tPFZG.png

For "case 1" imagine the yellow areas being holes in a larger polygon, and they share the red point.

For "case 2" the yellow area is the polygon with a hole that shares a (red) point with the polyline boundary.