Subject: [Acme] the standard

From: Josh Soref <[email-masked]>
Date: Sat, 18 Feb 2017 22:55:23 -0500

> Servers MUST NOT use the ACME URN namespace for errors other than the standard types.

"the standard" as written implies "this standard's".

I think what you want is "things defined by IETF/RFC including future ones".

I don't have spec language for such a thing. Sometimes the answer is
an IANA registry.

Again, I will eventually be sending more detailed comments about error
handling, this is merely from a line-by-line read.