For each issue anchor present in BASE 63279301bc non-test .py and absent on HEAD, the BASE comment/docstring block was re-attached at the HEAD location of the code it explained (matched by the distinctive code line / enclosing def). Sentences already covered by an existing HEAD comment were deduped; the issue number always survives. Insert-only: no code lines changed.
Repo scanners (check_subprocess_stdin, check-windows-footguns --all) flagged 21 sites where
the r3 single-line collapses lost stdin=DEVNULL, encoding='utf-8'/errors='replace', the
'# windows-footgun: ok' same-line marker, or the getattr(os, 'geteuid') gate. Each guard is
restored at the call site (real portability/hang fixes, not suppressions).
