The spec states that --page-id is both a multi-value option (i.e. comma-separated) and a range option (i.e. ellipsis allowing). Above that, core also implements the // prefix for regex values.

Naturally I would assume that I can combine these possibilities. But comma-separation only seems to work for literals, and regex is only activated for the expression as a whole or not at all. This is too restrictive IMO and should be fixed.