A related issue that has come up is <menu type=context> vs <menu type=popup>.

• 10070 pages use <menu type=context>
• 0 pages use <menu type=popup>
• 100 pages use <menu type=toolbar> or some other value

https://groups.google.com/a/chromium.org/d/msg/blink-dev/MkEDloT-yu8/wJhIK6jVSXMJ

Based on this I suggest we rename popup to context in the spec.

https://lists.w3.org/Archives/Public/public-whatwg-archive/2014Dec/0029.html