I can definitely picture a piece of content that's been scrubbed from everywhere except old copies of LLMs in which it still exists in a lossy form, with people trying to extract it from those old copies with the help of newer models. Private trackers have thrived for decades and will continue to do so because they allow a community to foster around a shared purpose (pardon the pun).

Although that being said, i doubt i would go through the trouble of signing up just for this purpose, personally.

Just do it like how libgen does. Maybe publish a RSS torrent feed people can subscribe to for the newer publications - knowing someone is curating the feed.

Weird to have open licensed stuff on private tracker.

And what are you going to train the models on?