RFC 6415, "Web Host Metadata", October 2011Source of RFC: IETF - NON WORKING GROUP
Area Assignment: app
Errata ID: 4811
Reported By: Dale R. Worley
Date Reported: 2016-09-26
Section 3.1.1 says:
The XRD "Link" element, when used with the "href" attribute, conveys a link relation between the host described by the document and a common target URI.
It should say:
The XRD "Link" element, when used with the "href" attribute, conveys a link relation between the host described by the document and a common target URI-reference.
The erratum changes the text to allow the value of the href attribute to be a URI-reference, that is, either a URI or a relative-reference.
It appears that the new text is what has always been intended, because RFC 6415 is taken from Extensible Resource Descriptor (XRD) Version 1.0
(http://docs.oasis-open.org/xri/xrd/v1.0/xrd-1.0.html) sections 2.6 and 1.5.2, which specifies the value to be an "anyURI" in the XML schema datatypes, which includes relative URIs. "URI-reference" in RFC 3986 is equivalent to "anyURI" in XML schema datatypes.
This erratum now matters, because draft-ietf-netconf-restconf makes significant use of href values that are relative URLs. Also, see the discussion at https://www.ietf.org/mail-archive/web/netconf/current/msg11768.html