Re: Which xkcd?
You mean you don't have the editor extension that does a search of the text archive for xkcd and return the appropriate URL for the cartoon you dimly remember? Back in the day, I used it often, mostly when composing email replies. (my MUA paid attention to $EDITOR)
I suddenly occurs to me that the "prison joke" (or variants like the "antarctic research station joke") about everybody telling jokes by number, because the all knew them. may have been started by a time-traveller after getting one too many of https://xkcd.com/936/
I guess I don't tell it right...