Is it legal to copy APIs and concepts of proprietary operating systems?

Question

Let's say I found publicly available documentation (not source code) for a proprietary operating system (for example, VxWorks). And let’s say I wrote my own operating system kernel, which would largely copy the API and concepts of this proprietary operating system.

(By "publicly available" I mean that I downloaded it from a torrent. And the developer of a proprietary operating system provides documentation only to clients)

Can the developer of this proprietary operating system make any claims against me if I publish my code on GitHub?

Thank you in advance!

Answer 1

I found the answer: Google LLC v. Oracle America, Inc.

From Wiki:

The Court issued its decision on April 5, 2021. In a 6–2 majority, the Court ruled that Google's use of the Java APIs was within the bounds of fair use, reversing the Federal Circuit Appeals Court ruling and remanding the case for further hearing