What is the issue with the HTML Standard?

The only requirement I see for optgroup is

An optgroup element is expected to be rendered by displaying the element's label attribute.

which seems insufficient for what the tests expect.

The option element also has a rather curious sentence that I don't quite understand:

indented under its optgroup element if it has one

Shouldn't that be defined through CSS, if there's any indentation to be done at all? Also, if you render option like suggested in the surrounding sentence, you might well end up with a rendering that doesn't support pseudo-elements, so something is missing there as well.

cc @mfreed7 @josepharhar @nt1m