I made an attempt to convert the manual to HTML 5, the rationale being that HTML 5 deprecates tt tag and recommends to replace it with tags like code, kbd, samp and var, which could be used in a more consistent way to achieve something closer to a semantic markup.
I tried then to use the replacement tags as consistently as possible in such a large body of text, but I realised that we perhaps need a kind of a style guide. Would you like to discuss it? Where would it best fit in the source code tree? Gintas