This software is 100% free. It would be ethical if you mention me in your extension that your using this API within an internal license file, and let me know what you create with it. I would be greatly happy!
I spent a good amount of time creating this, so being recognized is the only thing I ask in return of supplying free software. Being recognized is a good thing because it helps bring more developers to this project to help make it even more awesome.
I just don't like developers who steal peoples code and rebrand it as their own, it is ethically incorrect, but there is nothing I can do about that.
Example of a mention:
Made with Open Source software JSAPI by +Mohamed Mansour
Enjoy!