Depending on the width of the screen, punctuation can be orphaned

[ajeanmahoney]

For example, when the screen is set wide for https://red.staging.rfc-editor.org/info/rfc9877/, the period at the end of the last paragraph of "Status of This Memo" is on a line by itself. Seen in both Firefox and Chrome. Screen capture:

[holloway]

This is a difficult one. This isn't a regression afaik -- the same could happen on plain RFC HTML pages.

It's a hyperlink and then a character "." and the browser is at liberty to line break unless we we wrap both the link and the punctuation in a 'no wrap' container. We could convert the HTML to do that (perhaps if a link is followed by a "," or "." character but no others) but I suspect there will be other scenarios we'd miss.