Thank you @ryanjamurphy
I’ve used some so-called web page “markup” and “annotation” extensions in Chrome – unfortunately (or maybe fortunately) I do not remember their names because none of them were useful.
It seems to annotate web pages one needs to clone the page, then take steps to preserve the integrity of the original page while adding personal data (annotations) to it – and that path leads back to PDFs or WebArchives. 