I. It seems a little inconsistent that the Groff documentation's short TOC <https://www.gnu.org/software/groff/manual/groff.html#GNU-troff> does not include the chapter numbers present in the long TOC.
II. Also, one general issue, not just with the short TOC but in several places throughout the HTML page, is that the headers themselves are not clickable or accompanied by a link, which means users who've read yay far down the page may have to scroll away from where they are, and go to preceding chapters or sections (or teh hot meal sauce, even) to try and find a link to that actual section, so they can bookmark their spot. I'm not sure if either or both of these issues are fixable in groff.texi itself, or if this is best fixed in the relevant macro package. Sorry for hitting the list with a lot in a short period of time. I'm just doing that so it's on the record, lest I forget, move on, and ignore the issues in question, which some percentage of actual readers over the years probably has. Don't feel pushed, put down, or pressured by this "onslaught" though. There is no deadline. Ian