No specific means of browsing a web document should be preconceived, recommended or required.
Author must presume that document may be presented on any applicable device, which can handle such document. Especially formulations like "optimized for" are inadmissible.
Details: Author must not straightforwardly nor secretly reference any of all possible ways of presentation.
Links like "see right column", "in red frame in the document's bottom" etc. are forbidden. The document may be presented on device, which formats document in different manner than author presumes, or even may not represent it visually.
The accessibility of a web document should not prefer any specific means of browsing.
It is forbidden to deny to access to the document or its part on the base of automatic target device parameters retrieval. Automatic redirecting is allowed only when the target is alternative version of the document, which conveys the same information as the original document.
The document's content must not imply necessity of using device of particular type or make. If there is a link to a file, which can not be processed by browser, a reference to an appropriate application, that can handle such file, must be present. If this application is not freely available, user must be forewarned (see also The convey - external files).