If you look at all the master templates and figure out how they all fit together, one thing you will see is that you can actually build any system you want, as you can start by putting the doctype and the html tag, end with the html close tag and in between, you can set up any kind of parameterization and arrangement of master templates.
If you look at blank-master.{tcl,adp} you will see the actual html start tag and end tag, and see how they put any head tag stuff that is requested by the slave page author (look at the .tcl to see how it's done, and look at the ad_page_contract on that page for how to use anything there.
If you were to make a whole new system, you could write the docs as you have seen there, to describe your system. If you were to add a piece to the existing system, you can of course add docs to the ad_page_contract invocation in blank-master.
