[css-ui][css-pseudo][selection-api] Interop issue: Selecting the default quotes on <q> elements (+implications for selectable pseudo-elements)

[Psychpsyo]

The <q> element, by default, has a ::before and an ::after with quotes in it. In all browsers, these do not visually get selected when selecting the text around them. This is because pseudo-elements are currently not selectable in practice, since there's spec issues to resolve regarding copyability and DOM APIs. (see user-select)

In Firefox however, when actually querying the selected text (document.getSelection().toString()) or copying it with Ctrl+C, the resulting string does include quotes. However, this is not the quotes from the pseudos. Any (even partially) selected <q> element causes the copied text to include a " (U+0022 Quotation Mark) before and after the text from the <q> element. This ignores nesting level and Chrome does not do it at all.
EDIT: Nesting level isn't ignored, just reversed, but that's implementation bugs.

This seems like useful functionality and I think it might work as rough precedent for how selectable pseudos ought to be handled. (i.e. They'd be entirely invisible to DOM APIs and just magically inserted into the stringified Selection)
Though the inclusion around partial selections feels weird. Maybe this could get a new CSS property? (select-generated-content: always | in-range where in-range would only include them in a selection if the relevant element boundary is included)
Selections starting or ending inside ::before or ::after pseudos could just be placed around the originating element from the perspective of JS APIs.

[Psychpsyo]

I hope this is the right place for this, since I assume that css-ui would probably want to define the core behavior of this, with HTML and maybe the Selection API building on that.