How do you get the Dawnbringer Riven Icon?
It was a mission or event reward. Riot's description in the client reads: “Earned by participating in the 2017 VS. event.”
Is the Dawnbringer Riven Icon still available?
No. Riot tied the Dawnbringer Riven Icon to 2017 (mission reward), and it does not normally bring back past event rewards or bundles.
