A user asked this today:
And it was closed for being off-topic. Why? It seems like an objectively verifiable question to me. Was there a negotiation for the release of those prisoners or wasn't there? That's a yes or no question. If the answer is "we don't know", that's still an answer.
If there was a negotiation, who was the negotiating party?
If there was no negotiation, then there's plenty of room for argument as to whether it was a result of intimidation/pressure from Trump, or China, or whoever, but either way, it's perfectly reasonable to say that it's an act of goodwill by North Korea, which is also an answer.
The fact that Trump took credit for it is irrelevant. Of course he's going to take credit. So I don't see how this is off-topic.
I'm approaching this from the perspective of an uninformed 3rd party, which is what this site is supposed to be about.