This is the second time that I meet a discrepancy in between some implementations and the specification.
It creates confusion also for WPT which are not always following the spec.

• TypeError instead of NotAllowedError in navigator.clipboard.write(image/png DOMString)
• [Clipboard API] DataError vs NotAllowedError for malformed image data. Spec bug or wrong WPT?

Safari has been implementing what the specification has defined, but the error types from other browsers are slightly different.

It would be great to align the WPT and the specification in one way or the other to avoid the implementation ambiguities.

In issues Clarify promise rejection value #76, NotAllowedError was added for a couple of scenario.
And it was closed by #82