Rects merged by vertical overlap are the lines: a super/subscript,
formula or rotated run no longer opens a phantom line (5 was followed
by 10 one line later). List items and column paragraphs now count, as
both word processors number them; a line pushed past the page surface
is skipped so no number prints into the page gap.
A section narrower than the reserved sheet now splits the difference
between its insets instead of hanging it all on the right, and every
per-page layer draws from the box's own left — sheet, header/footer, page
border and line numbers. The ribbon's Size menu gains the same per-section
block Orientation already had.
The page grid was one repeating cycle, so every page had to be the same
size. It is now a table of height runs the placement pass grows as each
section's first page becomes known, and the sheets are one box per page
instead of a repeating gradient — .paper reserves the widest section's
paper, a narrower one takes the difference as a right inset.
Layout ▸ Orientation offers "this section"; the size stays document-wide
in the ribbon but round-trips per section from a file.
Continuous or per page, every nth line, empty lines counted or not —
LibreOffice's Tools ▸ Line Numbering, round-tripping as its
text:linenumbering-configuration and Word's w:lnNumType. CSS exposes no line
boxes, so the layer Range-selects each block and takes the distinct tops of
its client rects as its lines; LibreOffice renders the exported file with the
numbers in the same places.
Steffen Becker