I have some experience with it. I ran the tkbrowser (not sure what the name of the actual script is) that is included with that module. It didn't work. I made some changes and it ran. The Tk::HTML module seems to mostly support the header tags and a few other basic text rendering aspects of HTML like lists. From mucking about with the tkbrowser (or whatever it was) script, you can get a sense of what kind of calls are necessary to use the Tk::HTML module.

Frankly, HTML rendering is extremely complex (and tedious to program). The fact that this module does anything at all is nice. However, it is completely inadequate for anything except read-only efforts like man pages or perldoc converted to HTML. I don't think the package maintainer, Nick Ing-Simmons, is at all irresponsible (although it would have been nice to have at least a sample call to the library in the perldocs). Nick is extremely active in the Tk user community and the reason the Tk::HTML package has such a high version number is because the rest of the Tk packages have such a high version number. Given that Nick appears to have not worked on the Tk::HTML module since 1998, I'd say that there is not going to be much progress in that area unless you're willing to take it over.