Honestly, just read the brief, it goes into detail the precedent involved in their argument: https://www.eff.org/files/2014/11/07/google_v_oracle_computer-scien

Honestly, just read the brief, it goes into detail the precedent involved in their argument: https://www.eff.org/files/2014/11/07/google_v_oracle_computer-scientists-certpetition-amicus-brief_14-410_final.pdf https://www.eff.org/files/2014/11/07/google_v_oracle_compute... for example... Ninth Circuit law—which should have been controlling in this case—was the same: the “functional requirements for compatibility” between computer programs “are not protected by copyright.” Sega Enters., Ltd., v. Accolade, Inc. Also, an API is much more than you think. An API might be Windows' system APIs which applications use to interact with the operating system -- put a license behind that and WINE is gone overnight. An API is also totally indistinguishable from a network protocol, in both a technical and legal sense.