Content negotiation for language and format? Not in any human-usable system, please. Sharing a URL then getting content in a different language is incredibly an

Content negotiation for language and format? Not in any human-usable system, please. Sharing a URL then getting content in a different language is incredibly annoying. There may be no alternative for home pages, and using the Accept-Lang header is nicer than using the broken geo system for sure. But it makes no sense to have a link to a document and get completely different content back based on language. And file extensions are needed since browsers don't expose a way to ask for, say, PDFs or images over HTML.