I thought there was text somewhere that says that "Applies to: all elements" means that it applies to elements and to the ::before and ::after pseudo-elements (or similar for "Applies to: block-level elements", "Applies to: elements that establish block formatting contexts", etc.).

However, I can't find any such text.

It's possible that the text belongs in css-pseudo, although I tend to think it might belong where we define the "Applies to" line (see also speced/bikeshed#617), or in both places.