California has prohibited companies from using NDAs to stop employees from talking about harassment or discrimination at work.

Is this really limited to employees only? What about other workers, such as temps, gig workers, and other "independent contractors"?

The other unjust kind of NDA is that which covers generally useful technical information. My experience with MIT's Xerox laser printer taught me that it is wrong to sign a nondisclosure agreement covering generally useful technical information such as software. and I determined never to agree to them. I have never made an exception for any software or knowledge I have.

Occasionally I have agreed to a nondisclosure agreement for software knowing that I would never get a copy pf that software, so the agreement would be void. After all, it's nonfree software, so I do not want to run it!