I mean, it's explained very clearly in the commit message that's linked?
Since the page where the bug manifests itself already has responsive CSS
styling, we can quirk TextAutoSizing to skip adjusting for it, at least
until we figure out why we are calculating RenderBlockFlow width inconsistently:
https://bugs.webkit.org/show_bug.cgi?id=275223
That's even better than a comment, because you can git blame for it and get the full context of the issue (from the bug thread that proposed it to all of the documentation of the investigation done for both bugs)