This is the Tribblix website.
It uses nanoc as a Static Site Generator to assemble the various page fragments.
The only slightly odd thing is the way that the overlay list is constructed dynamically. But everything is hidden in the manage-site.sh script.
For the handbook, in content/Use, you should edit the body files. The html files there are updated by the mk-handbook.sh script, which appends the previous/next links at the bottom.