llms.txt: a proposed standard no major AI platform has confirmed it uses

The llms.txt file is a proposed Markdown standard that helps AI systems find a website's most important pages, but no major AI platform has confirmed it actually uses the file. Google has rejected it, crawlers rarely request it, and only about 10% of sites have adopted it. Despite weak evidence it improves AI citations, it's still worth creating because it takes minimal time and could matter if AI agents eventually rely on machine-readable site guides.