The recent sale included a new session of GOG Connect. And I have Sunless Sea on Steam, so it is now here, too. Yay! However, I have the DLC - Zubmariner on Steam. And that did not come over.

Boohoo.

I think there was a statement about DLCs, that they aren't reported by the steam api so GOG has no way of validating them. So no connect for DLC only games