NetFront v3.3, v3.4 and v3.5 browser engines, utilized in the Sony Ericsson phone models within the scope of this document, includes support for WAP 2.0, WML, HTML 4.01, XHTML and CSS2.
The browser uses Rapid-Render, which is an incremental rendering technology that significantly accelerates the presentation of web pages, and Smart-Fit Rendering, a rendering technology that intelligently renders web pages to fit the screen width of mobile devices, eliminating the need for horizontal scrolling.
The document is intended for content developers for Sony Ericsson phones. The main purpose is not to instruct the reader how to write HTML and XHTML content, but to describe how the phone browser interprets tags and attributes.

You can download this document from http://developer.sonyericsson.com/getDocument.do?docId=88004