1From the abstract:
2  The XHTML Basic document type includes the minimal set of modules
3  required to be an XHTML host language document type, and in addition
4  it includes images, forms, basic tables, and object support. It
5  is designed for Web clients that do not support the full set of
6  XHTML features; for example, Web clients such as mobile phones,
7  PDAs, pagers, and settop boxes. The document type is rich enough for
8  content authoring.
9
10  XHTML Basic is designed as a common base that may be extended. For
11  example, an event module that is more generic than the traditional
12  HTML 4 event system could be added or it could be extended by
13  additional modules from XHTML Modularization such as the Scripting
14  Module. The goal of XHTML Basic is to serve as a common language
15  supported by various kinds of user agents.
16
17The document type definition is implemented using XHTML
18modules as defined in "Modularization of XHTML", found in
19ports/textproc/xhtml-modularization.
20