The plugin was merged into the WebFinger plugin.
This plugin implements WebFinger web pages: http://tools.ietf.org/html/rfc7033#section-3.2
Suppose an application is defined to retrieve metadata information about a web page URL, such as author and copyright information. To retrieve that information, the client can utilize WebFinger to issue a query for the specific URL.
This plugin requires the WebFinger plugin (version >= 3.0.0).
Thanks to @willnorris for the idea!