In the Python module: Attempting to open font with FSType 2 (Restricted License) fails with nonspecific "OSError: Open failed"

[WinkelCode]

I was trying to automate something with FontForge, but kept running running into:

The PostScript font name "[REDACTED]" is invalid.
It should be printable ASCII,
must not contain (){}[]<>%/ or space
and must be shorter than 63 characters
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: Open failed

It took me way too long to figure out that the issue was the restricted license flag, rather than the invalid PostScript font name.

It would be very useful if this error reason was disclosed in some way in the error message.

Edit: For future context: I am using the GitHub Actions build of this commit: 9964090 (latest as of posting)