HTTP and HTML are very common acronyms; nobody should be getting out of high school these days without knowing them, and if they somehow managed to do so, they're darned sure not reading HN. Even SQL is pretty hard to avoid if you've been in an IT-adjacent industry for a while.

However, MLIR is a highly-specialized term. The problem with failing to define a term like that is that I don't know up front if I'm the target audience for the article. I had to Google it, and when I did that, all I found at first were yet more articles that failed to define it.

Wikipedia gets the job done, but these days, Wikipedia is often a long way down the Google search results list. I think they downranked it when they started force-feeding AI answers (which also didn't help).