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
http://www.robotstxt.org/ 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.