RedHat urges US Supreme Court to support unrestricted use of software interfaces
redhat.com
redhat.com
If they lose the world loses.
The docket also links to the full supporting argument provided by RedHat (and others).
[0] - https://www.supremecourt.gov/docket/docketfiles/html/public/...
Software interfaces look to me like a "method of operation", only the implementation (the lines of code to run the interface) is subject to copyright.