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xkcd #2827: Brassica
(imgs.xkcd.com)
Alt text:
Sequoia Brussels sprouts are delicious but it's pretty hard to finish one.
Alt texts have a purpose. Some people are dependent on them. But sure, make fun of me for caring, go ahead.
You are right, but for xkcd it's a concept to have a second joke in the alt text since forever. There used to be a transcript of all comics right on the site available for those that need it, but it has been discontinued, probably in favor of explainxkcd.com, where you'll still find a transcript for every comic.
Thanks! I didn't know that