Matthias Pfefferle

This plugin enables “Well-Known URIs” support for WordPress (RFC 5785: http://tools.ietf.org/html/rfc5785).
From the RFC:
It is increasingly common for Web-based protocols to require the 
 discovery of policy or other information about a host (“site-wide 
 metadata”) before making a request. For example, the Robots 
 Exclusion Protocol <a href="http://www.robotstxt.org/" rel="nofollow ugc">http://www.robotstxt.org/</a> specifies a way for 
 automated processes to obtain permission to access resources; 
 likewise, the Platform for Privacy Preferences 
 tells user-agents how to discover privacy policy beforehand.
While there are several ways to access per-resource metadata (e.g., 
 HTTP headers, WebDAV’s PROPFIND [RFC4918]), the perceived overhead 
 (either in terms of client-perceived latency and/or deployment 
 difficulties) associated with them often precludes their use in these 
 scenarios.
When this happens, it is common to designate a “well-known location” 
 for such data, so that it can be easily located. However, this 
 approach has the drawback of risking collisions, both with other such 
 designated “well-known locations” and with pre-existing resources.
To address this, this memo defines a path prefix in HTTP(S) URIs for 
 these “well-known locations”, “/.well-known/”. Future specifications 
 that need to define a resource for such site-wide metadata can 
 register their use to avoid collisions and minimise impingement upon 
 sites’ URI space.

/.well-known/

This plugin enables "Well-Known URIs" support for WordPress

Will Norris

Enables WebFinger (<a href="http://tools.ietf.org/html/rfc7033" rel="nofollow ugc">RFC 7033</a>) support for WordPress.
About WebFinger:
<blockquote>
WebFinger is used to discover information about people or other entities on the Internet that are identified by a URI using standard Hypertext Transfer Protocol (HTTP) methods over a secure transport. A WebFinger resource returns a JavaScript Object Notation (JSON) object describing the entity that is queried. The JSON object is referred to as the JSON Resource Descriptor (JRD).
</blockquote>
(quote from the <a href="http://tools.ietf.org/html/rfc7033" rel="nofollow ugc">RFC</a>)

/.well-known/ vs WebFinger