This is the key issue. It seems like a copyright license to code under GPL would be commercial, in the sense that the parties are exchanging a license for the recipient undertaking the GPL obligations. Whether it's "negotiated" seems like a more difficult question.

One interpretive guide could be to look to the reason for the provision. I suspect the purpose was to allow for source-code escrow agreements in things like enterprise software deals. It would be odd for the enforceability of those provisions to turn on the degree to which the parties "negotiated," so I suspect this will be a low bar.

Rather, I suspect the term "negotiated" is intended to block end-runs around the default rule. Otherwise, governments could obligate copyright holders to burden their code with GPL-like code, e.g., a reg saying you can only provide voting machines if they are based on a modified version of the Linux kernel.

So I think GPL source-code disclosure obligations remain enforceable, absent coercive acts by a government to force parties to undertake those obligations. But this is really speculative.