This uses a relaxed HTML 4 DTD, I assume compatable with XHTML, judging by the balancing of the open and close tags. This is not WYSIWYG, but a text editor with programming hooks. I would assume that it might produce blocks for Perl and C, balancing brackets correctly.
There is an autowrap feature. The application runs under X11, like Open Office does, but it doesn't appear to know how to open the file being edited in a browser. I may have to config that. It is looking for reasonable browsers but they are not installed here or are not in standard places, so as it stands this is less useful than plain old emacs, but I am not giving up on it.
It was relatively easy to add style to this and there is a facility for adding an external style sheet. I had to resort to editing style by hand to effectively add features incrementally as the dialogue seemed to get lost about what object I was adding to. I generally add style only to the body element as it is guarenteed to apply to all subobjects. I can fool the CSS dialogue by just plunking a value where I want it in the sheet and then setting up the attribute by hand.