Automatically fetches and appends all pages of comments on AO3 — et carthago delenda est. Matches are AO3 and its TLDs that are not redirects directly to .org (no point in matching the TLDs that are simply redirects — cf. https://archiveofourown.org/faq/accessing-fanworks#archiveurl).
A friend asked if it would be possible to view all comment threads in one swell foop (joke, not typo). I was sure that it could be done, but figured that a JS userscript probably could look ahead to n-many pages seeking each page of comments that has <li class="next" title="next"><a data-remote="true" rel="next" href="/comments/show_comments?page=5&work_id=28934610">Next →</a><li> and store those in a virtual memory (rather than rendering the actual HTML) until finding the final page that lacks that button, then append those pages' comments to the bottom of the first page.
I'm OK at CSS, but am a toddler-with-building-blocks level in JS, and so (while I don't care to admit this, my conscience demands that I do) I had to resort to asking Google search's "AI Mode" for the actual coding needed: this is way beyond my current level of skill, but I didn't want to let my friend down either, so... there you have it.
NB: This functions for single-chapter works' multiple pages of comments, and for the expansion of multiple truncated-continued-subthreads of a multi-chapter work's single chapter — but I need to find a multi-chapter work with a single chapter that has multiple pages of comments in order to test that. It does not yet work for multi-chapter works in Entire Work view.
I tested in Tampermonkey in Chrome and Violentmonkey in Firefox, both in a WIN 11 environment. Attached images show the four stages:
