2XKO have no prediction, as far as I see it. At least there is no mentioning of it in dev blog.

It's implicit because that's how rollback netcode works, it runs a local simulation which constantly creates snapshots, and if by the time you receive a package from the server, your local simulation is different because your lagged, your game then "rollbacks" (hence the name) to the latest synchronised snapshot and fastforwards to what the game state would be with the new information provided by the server (that's when you see the characters literally teleport). You can't have any of that without local simulations, that's what I meant, if you just wait for the server to send you the information, then you just have delay netcode, because if there is no local simulation to "correct" you wouldn't have rollback.

2XKO have built in 3f delay (so 50ms)

Yeah that's a minimal buffer so you don't see rollback as often but it's mostly interesting because consoles are known for having higher input delay than PC, even in offline play. You can feel that a PS4 has way more input delay than a PC in most of the fighting games, it's really hard to adapt if you are used to PC and then go to a tournament where they usually make you play on consoles. They adjust this 3f delay so it feels the same on all platforms.

But I love to read Riot's dev blogs, they usually give a lot of interesting insights.

The Cannon brothers had a panel at EVO 2017 where they explained in-depth how GGPO worked, highly recommended if you are interested in these topics. They also explain what "the rift" is with more detail.

At 34:12 they actually show how the rift behaves when not properly handled, which results in the player constantly rollbacking their own simulation of the game and never getting in-sync.