Two follow-ups to the empty-page fallback:
- A page counts as empty only when nothing on it was skipped: its only
notes are the page's own (art off the artboards, art past the page). A
page whose only content couldn't be read, such as an image that can't
be decoded, keeps its notes and goes through the usual check against
the editing data, instead of being replaced by it unchecked.
- With textAs: outlines, the document read from the editing data alone
has its type outlined. The usual path takes outlines from the page,
but an empty page (or a text-only placeholder, #1387) has none to give.