[esjr]

So no one has heard of RFC6648 ? https://tools.ietf.org/html/rfc6648

[wlll]

> "…in practice the benefits [of the "X-" convention] have been outweighed by the costs associated with the leakage of unstandardized parameters into the standards space."

Honestly, prefixing silly, fun or extra headers with X- like in this scenario seems pretty harmless.