[ub] cleanups and feedback from initial reviewers#8739

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notadragon wants to merge 10 commits intocplusplus:ub-ifndrfrom

notadragon:ub-ifndr-cwgreview1

Commits on Feb 11, 2026

[ifndr] more feebdack from Shafik
joshuaberne
committed

Commits on Feb 18, 2026

[ifndr]: added missing entries brought up by Alisdair
joshuaberne
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