Information pertaining to all Function-Call drops. This should be passed in if the drop will be a Function-Call drop.
The top level array indicates a different set of methods that can be called for every key use. It is possible that for a given key use, no methods are called thus acting as a "free" key use whereby the use is reflected on-chain but no assets are transferred. If a given key use does not have an undefined set of methods, when it is used, all the methods in the set will be called.