> That's not really the court's responsibility.
Yes, it is.
> There is no legal definition of "interface" or "implementation".
There is a legal definition of what is included, and what is excluded, from copyrightability, and (though its quite fuzzy, in large part because it was trying to incorporate a fuzzy judicial doctrine grounded in the First Amendment into the statute) what is included, and excluded, from "fair use" even if it otherwise violated copyright.
The courts job is very much to test existing concrete things against those definitions.
