Pretty sure assassin roughly means person who you hire to kill people.

The difference is effectively one of motive and contract.

If I’m personally wronged by the victim and I personally plan to kill them myself, that’s first degree murder.

If I don’t leave the house intending to kill someone, but end up in a fight or situation where I end up intending to cause harm to someone (even if it’s protecting myself), and end up killing someone, that’s generally second degree murder.

Now if I’m wronged by someone, plan to have them killed, but don’t want to do it myself, so I set up a contract with a hit man and pay money to have a target killed. That’s assassination.

This is possibly regarding the updated OS that’s on SteamDeck, which is not built on the same distro of Linux as the older SteamOS from back in the day.