> Isn't the correct analogue to the API code the instruction book rather than the resulting ledger templates? I would say it's the latter and not the former. A

> Isn't the correct analogue to the API code the instruction book rather than the resulting ledger templates? I would say it's the latter and not the former. APIs aren't instructions in and of themselves, they are instruction identifiers. And the instructions they identify correspond to interactions in a working system. If one wanted to recreate the working system, they'd be hard pressed to do so without recreating instruction identifiers. This isn't just an interoperability issue, but also because experienced practitioners have certain expectations re instructions semantics. Those semantics are often unexpressed directly and come from for example their organization into a given module. > But here they're alleging something further: that the API (instruction book) itself has been copied. This is where I'm really puzzled. The API is not the instruction book. The API is a method of interacting with an invented system. You cannot use the API in isolation from the system, by itself it's largely useless. You can't take the API, read it, and then be able to use the system. You need the API to use the system as well, by definition it cannot be used without an API. You could say that the instructions and the ledger templates are fused and inseparable here, but that's only in cases where no other documentation exists which is not the case for the majority of system on the level of Java.