It is a shame that the reviewed extension doesn't have its own documentation and is mixed with the type_traits existing documentation.
If you just open the tarball you have the doc and there is a page just for the addition + links to each of the traits (type_traits/libs/type_traits/doc/html/boost_typetraits/category/value_traits/operators.html).
The problem here is that the html files have the wrong svn mime-type property (text/plain), set it to text/html and the docs should be browsable directly from svn.
I have changed that so that it now works better with the link you mentionned: http://svn.boost.org/svn/boost/sandbox/type_traits/libs/type_traits/doc/html... Note that you will not get the proper formatting. To get the proper formatting of the doc, you need to open the tarball. Frédéric