This document type declaration refers to the HTML DTD with the `HTML.Forms' entity defined as `IGNORE' rather than `INCLUDE'. Documents which contain <FORM> elements do not conform to this DTD, and must use the level 2 DTD.
<!-- html-1.dtd Document Type Definition for the HyperText Markup Language with Level 1 Extensions (HTML Level 1 DTD). $Id: 95.htm,v 1.1.1.1 1998/09/05 02:18:12 baccala Exp $ Author: Daniel W. Connolly <connolly@w3.org> See Also: http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html --> <!ENTITY % HTML.Version "-//IETF//DTD HTML 2.0 Level 1//EN" -- Typical usage: <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML Level 1//EN"> <html> ... </html> -- > <!-- Feature Test Entities --> <!ENTITY % HTML.Forms "IGNORE"> <!ENTITY % html PUBLIC "-//IETF//DTD HTML 2.0//EN"> %html;