I asked three different commercially available LLMs the same question: Which TLDs have the same name as valid HTML5 elements? This is a pretty simple question to answer. Take two lists and compare them. I know this question is possible to answer because I went through the lists two years ago. Answering the question was a little tedious and subject to my tired human eyes making no mistakes. So surely this is the sort of thing which an LLM excels at, right? Wrong! Here's how the three big beasts ...