It goes right back to the spec. The W3C drones on and on for 132 words as to what "NO CONTENT" means. But devotes merely seven words to commerce. From that, all

It goes right back to the spec. The W3C drones on and on for 132 words as to what "NO CONTENT" means. But devotes merely seven words to commerce. From that, all that follows. https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.3 https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec1...