Contains renderers and parsers for both XML and HTML 5
document fragments, which share data structures so that
it's easy to work with both. Document fragments are bits
of documents, which are not constrained by some of the
high-level structure rules (in particular, they may
contain more than one root element).
Note that this is not a compliant HTML 5 parser. Rather,
it is a parser for HTML 5 compliant documents. It does not
implement the HTML 5 parsing algorithm, and should
generally be expected to perform correctly only on
documents that you trust to conform to HTML 5. This is
not a suitable library for implementing web crawlers or
other software that will be exposed to documents from
outside sources. The result is also not the HTML 5
node structure, but rather something closer to the physical
structure. For example, omitted start tags are not
inserted (and so, their corresponding end tags must also be
omitted).
