!!! Overview [1]
[{$pagename}] is part of [OpenID Connect Discovery] and is the process of determining the location of the determining the [OpenID Connect Provider] for a particular [End-User]

[{$pagename}] is [OPTIONAL].

If a [Relying Party] knows the [OpenID Connect Provider]'s Issuer location through an out-of-band mechanism, then the [Relying Party] can skip [{$pagename}].

[{$pagename}] requires the following information to make a discovery request:
* [resource] - [Identifier] for the target [End-User] that is the subject of the discovery request.
* [host|Hostname] - Server where a [WebFinger] service is hosted.
* rel - [URI] identifying the type of service whose location is being requested.

[OpenID Connect] uses the following discoverable rel value in [WebFinger] ([RFC 7033]):
* OpenID Connect Issuer (http://openid.net/specs/connect/1.0/issuer)

The [Relying Party] applies normalization rules to the Identifier to determine the Resource and Host. Then it makes an HTTP GET request to the Host's [WebFinger] ([RFC 7033]) [endpoint] with the resource and rel parameters to obtain the location of the requested service. All [WebFinger] communication [MUST] utilize [TLS] in the manner described in Section 7.1.

The Issuer location [MUST] be returned in the [WebFinger] response as the value of the href member of a links array element with rel member value http://openid.net/specs/connect/1.0/issuer. (Per Section 7 of [WebFinger] [RFC 7033], obtaining the [WebFinger] response may first involve following some redirects.)

The returned Issuer location [MUST] be a [URI] [RFC 3986] with a [URI Scheme] component that [MUST] be [HTTPS], a [URI] host component, and optionally, port and path components and no query or fragment components. 

Note that since the Host and Resource values determined from the user input Identifier, as described in Section 2.1, are used as input to a [WebFinger] request, which can return an Issuer value using a completely different scheme, [host|Hostname], [port], and [URI Path], no relationship can be assumed between the user input Identifier string and the resulting Issuer location.

Before you can perform a Query for a resource you need the related problem of how to know, for some particular [host|Hostname], where to get the [{$pagename}] data. The [host-meta] file, a [well-known] [URL] proposal from [Web Host Metadata|Web host-meta data] maybe helpful. ([We] have not seen any wide implementation of this).

For example the [Host-meta] [Well-Known URI] [data] for [Google] is here:
%%prettify 
{{{
http://gmail.com/.well-known/host-meta
}}}
/%

Which provides an [XML]-[XRD] document:
%%prettify 
{{{
<?xml version='1.0' encoding='UTF-8'?>
<!-- NOTE: this host-meta end-point is a pre-alpha work in progress.   Don't rely on it. -->
<!-- Please follow the list at http://groups.google.com/group/webfinger -->
<XRD xmlns='http://docs.oasis-open.org/ns/xri/xrd-1.0' 
     xmlns:hm='http://host-meta.net/xrd/1.0'>
  <hm:Host xmlns='http://host-meta.net/xrd/1.0'>gmail.com</hm:Host>
  <Link rel='lrdd' 
        template='https://profiles.google.com/_/webfinger/?q={uri}'>
    <Title>Resource Descriptor</Title>
  </Link>
</XRD>
}}}
/%

Now that we know the [URL] for the 'rel' parameter, we can query [Google] provides a [{$pagename}] for Gmail users. 
%%information
This discovery does not appear to work for [G-Suite] users.
%%

A [URL] like: [https://profiles.google.com/_/webfinger/?q=jwilleke@gmail.com&rel=http://openid.net/specs/connect/1.0/issuer|https://profiles.google.com/_/webfinger/?q=jwilleke@gmail.com&rel=http://openid.net/specs/connect/1.0/issuer|target='_blank'] which returns a [XML]-[XRD] document:
%%prettify 
{{{
<?xml version='1.0'?>
<XRD xmlns='http://docs.oasis-open.org/ns/xri/xrd-1.0'>
    <Subject>acct:jwilleke@gmail.com</Subject>
    <Alias>http://www.google.com/profiles/jwilleke</Alias>
    <Link rel='http://portablecontacts.net/spec/1.0' href='http://www-opensocial.googleusercontent.com/api/people/'/>
    <Link rel='http://portablecontacts.net/spec/1.0#me' href='http://www-opensocial.googleusercontent.com/api/people/110925871223838855670/'/>
    <Link rel='http://webfinger.net/rel/profile-page' href='http://www.google.com/profiles/jwilleke' type='text/plain'/>
    <Link rel='http://microformats.org/profile/hcard' href='http://www.google.com/profiles/jwilleke' type='text/plain'/>
    <Link rel='http://gmpg.org/xfn/11' href='http://www.google.com/profiles/jwilleke' type='text/plain'/>
    <Link rel='http://specs.openid.net/auth/2.0/provider' href='http://www.google.com/profiles/jwilleke'/>
    <Link rel='describedby' href='http://www.google.com/profiles/jwilleke' type='text/plain'/>
    <Link rel='describedby' href='https://www.google.com/s2/webfinger/?q=jwilleke@gmail.com&amp;fmt=foaf' type='application/rdf+xml'/>
</XRD>
}}} /%

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
----
* [#1] - [OpenID Provider Issuer Discovery|https://openid.net/specs/openid-connect-discovery-1_0.html#IssuerDiscovery|target='_blank'] - based on data observed:2015-05-18
* [#2] - [Discovery: Webfinger and OpenID Connect|WebFinger|http://www.windley.com/archives/2010/11/discovery_webfinger_and_openid_connect.shtml|target='_blank'] - based on data observed:2015-05-18