November 1st 2016 has come and gone so it's time to disable this.
Also, add comments explaining why the things that have been whitelisted
have been (to avoid more being added without good justification).
This is the (partially) documented public API for Homebrew.
The main class you should look at is the {Formula} class (and classes linked from there). That's the class that's used to create Homebrew formulae (i.e. package descriptions). Assume anything else you stumble upon is private.