Cookbook
Worked answers to the questions addon authors ask most.
Powers on an entity
Detecting, reading, granting, revoking and suppressing powers from Java, and storing state for each entity.
Origins from Java
Getting an origin's powers, finding out what a player has chosen, and doing both without a hard dependency.
Writing actions
A worked action of each flavour, plus taking a nested action and running it yourself.
Writing conditions
A worked condition of each of the eight flavours, plus comparisons and expression fields.
Hooking the game
Making vanilla respect a power without fighting every other mod for the same instruction.