> * For project maintainers: The SF Conservancy can't prevent developers from working on their own project, because it is GPL-licensed and copyright holders can't retract GPL licensing once it's been given.

No, they can't retract your permission to use your own software, but they can prevent you from going after infringing parties if SF Conservancy holds the copyright.

And at that point, why assign them copyright at all?

Because 99.9% of developers aren't willing to suffer the time and expense of investigating violations and enforcing their copyrights in federal court.

So why can't the SF Conservancy assist by making resources available to developers who are interested?

If pro bono legal representation were provided, I wager a number of developers would take up that offer.

I can't speak for them, but I can tell you that would add an enormous amount of overhead and risk for the lawyers involved. If you assign them your copyrights, their job is just to find GPL violations from the pool of projects they have the rights to and then initiate an action in court, which they do for a living. Without assignment, they can no longer proactively investigate with any reasonable chance of success, and they have to find a violation that's in a goldilocks zone; they need a GPL author whose rights have been violated and is willing to make a long term commitment to actively participating in litigation, that they know will communicate with them as needed, and who won't suddenly move to Nepal or be convinced by people online that they need to drop the suit or something.

If the developer owns the code: The violator may offer to make things right by releasing the code. The developer may choose to accept this offer, leaving the lawyer with little.

If the lawyer owns the code: The violator's offer to simply release the code is refused by the lawyers, who go for the jugular and try to bleed the violating company for as much money as they can.

>copyright holders can't retract GPL licensing once it's been given

This is only true for GPLv3, and not GPLv2.

A specialist lawyer paid to investigate the subject and write their legal opinion says GPLv2 can’t be revoked (section 7.4 GPLv2 Irrevocability): https://copyleft.org/guide/comprehensive-gpl-guidech8.html#x...

Of course, many other non-specialists have contrary opinions. If you have a link to a legal opinion to the contrary (by a lawyer skilled in the relevant areas), could you please share it?

No, I don't. I was just going off what I have read in the past. I didn't follow it too closely.

Do you have any reliable sources for that being the case? Everything I've read, pretty much ever, about the GPLv2 indicates that the version of code released under the GPLv2 is forever available under the GPLv2. You can change the license, but people are always free to use the last version that was released under GPLv2.

I don't know off the top of my head but searching for "rescinding the GPL" should turn some stuff up. It's at least a grey area.

So any Linux kernel contributor in the last 30 years can pull their license and force an immediate "emergency rewrite" of everything they've contributed? Since other Linux developers would no longer have a license to use it?

That seems unlikely, or somebody would do it just for the laughs. (I certainly would)

There were threats of it around the time the CoC was added.

That sounds like internet drama and not a serious threat. I think they're powerless to do anything.