New principle: all new headers shall be structured headers

[annevk]

To not expand on the number of custom header parsers in HTTP libraries, all new headers must follow https://tools.ietf.org/html/draft-ietf-httpbis-header-structure. This is already de facto enforced, but it would be good to have it documented.

cc @mnot (feel free to unsubscribe, but I thought you might want to know)

[LeaVerou]

If we resolve to work on this, I wonder if this means we should add a new section for HTTP-related principles?

[cynthia]

https://w3ctag.github.io/design-principles/#new-http-header-syntax

[torgo]

Discussing today and we think we can close this.