Editing Uniform Resource Identifier (section)

=== Refinement ===

In December 1994, {{IETF RFC|1738}} formally defined relative and absolute URLs, refined the general URL syntax, defined how to resolve relative URLs to absolute form, and better enumerated the URL schemes then in use.{{Ref RFC|1738}}  The agreed definition and syntax of URNs had to wait until the publication of IETF {{IETF RFC|2141}}{{Ref RFC|2141}} in May 1997.

The publication of IETF {{IETF RFC|2396}}{{Ref RFC|2396}} in August 1998 saw the URI syntax become a separate specification{{Ref RFC|2396}} and most of the parts of RFCs 1630 and 1738 relating to URIs and URLs in general were revised and expanded by the IETF. The new RFC changed the meaning of ''U'' in ''URI'' from "Universal" to "Uniform."

In December 1999, {{IETF RFC|2732}}{{Ref RFC|2732}} provided a minor update to <nowiki>RFC 2396</nowiki>, allowing URIs to accommodate [[IPv6]] addresses. A number of shortcomings discovered in the two specifications led to a community effort, coordinated by <nowiki>RFC 2396</nowiki> co-author [[Roy Fielding]], that culminated in the publication of IETF {{IETF RFC|3986}}{{Ref RFC|3986}} in January 2005. While obsoleting the prior standard, it did not render the details of existing URL schemes obsolete; <nowiki>RFC 1738</nowiki> continues to govern such schemes except where otherwise superseded. IETF {{IETF RFC|2616}}{{Ref RFC|2616}} for example, refines the <code>http</code> scheme. Simultaneously, the IETF published the content of <nowiki>RFC 3986</nowiki> as the full standard STD 66, reflecting the establishment of the URI generic syntax as an official Internet protocol.

In 2001, the [[World Wide Web Consortium|World Wide Web Consortium's]] (W3C) Technical Architecture Group (TAG) published a guide to [[best practices]] and canonical URIs for publishing multiple versions of a given resource.<ref>{{cite web |last1=Raman |first1=T.V. |title=On Linking Alternative Representations To Enable Discovery And Publishing |url=https://www.w3.org/2001/tag/doc/alternatives-discovery.html |website=W3C |access-date=6 December 2020 |date=1 November 2006}}</ref> For example, content might differ by language or by size to adjust for capacity or settings of the device used to access that content.

In August 2002, IETF {{IETF RFC|3305}}{{Ref RFC|3305}} pointed out that the term "URL" had, despite widespread public use, faded into near obsolescence, and serves only as a reminder that some URIs act as addresses by having schemes implying network accessibility, regardless of any such actual use. As URI-based standards such as [[Resource Description Framework]] make evident, resource identification need not suggest the retrieval of resource representations over the Internet, nor need they imply network-based resources at all.

The [[Semantic Web]] uses the HTTP URI scheme to identify both documents and concepts for practical uses, a distinction which has caused confusion as to how to distinguish the two. The ''TAG'' published an e-mail in 2005 with a solution of the problem, which became known as the ''httpRange-14 resolution''.<ref>{{cite web |last1=Fielding |first1=Roy |title=[httpRange-14] Resolved |url=https://lists.w3.org/Archives/Public/www-tag/2005Jun/0039.html |website=W3C Public mailing list archives |access-date=6 December 2020 |date=18 June 2005}}</ref> The W3C subsequently published an Interest Group Note titled "Cool URIs for the Semantic Web", which explained the use of [[content negotiation]] and the [[HTTP 303]] response code for redirections in more detail.<ref>{{cite web |editor-last1=Sauermann |editor-first1=Leo |editor-first2=Richard |editor-last2=Cyganiak |first1=    Danny |last1=Ayers |first2=Max |last2=Völkel |title=Cool URIs for the Semantic Web |url=https://www.w3.org/TR/cooluris/ |website=W3C |access-date=6 December 2020 |date=3 December 2008}}</ref>