Subject: [Acme] Small tweaks to HTTP section

From: Jacob Hoffman-Andrews <[email-masked]>
Date: Tue, 9 Aug 2016 18:00:08 -0700

https://github.com/ietf-wg-acme/acme/pull/168

-In all HTTPS transactions used by ACME, the ACME client is the HTTPS
client and
-the ACME server is the HTTPS server.
+In most HTTPS transactions used by ACME, the ACME client is the HTTPS
client
+and the ACME server is the HTTPS server. The ACME server acts as an
HTTP and
+HTTPS client when validating challenges via HTTP.
+
+ACME clients SHOULD send a User-Agent header in accordance with
+{{!RFC7231}}, including the name and version of the ACME software in
+addition to the name and version of the underlying HTTP client software.
+
+ACME clients SHOULD send an Accept-Language header in accordance with
+{{!RFC7231}} to enable localization of error messages.