Widow-orphan control was hardcoded on. It is a per-paragraph property in
both formats, so a file that turns it off paginated differently from
Word and LibreOffice.
Stored as the widowControl attr next to breakBefore. DOCX resolves
w:widowControl direct-then-style-chain-then-docDefaults; ODF reads
fo:widows/fo:orphans, where only an explicit 0 means off (absent is the
XSL-FO default of 2). Export rides the existing PBX sentinel rather than
adding a pass.