Don't you want to mention SET PARSER HTML on http://docs.basex.org/wiki/Parsers ?
Also there is nothing 'bad' about the HTML... It is valid form of one of the html versions mentioned on http://docs.basex.org/wiki/Serialization .
Indeed, the versions that SET PARSER HTML will support should please be documented there on http://docs.basex.org/wiki/Parsers .