How do you get the Unconquered Frontier Icon?
It was a mission or event reward. Riot's description in the client reads: “Unlocked by engaging with the 2018 Jungle Lore Update.”
Is the Unconquered Frontier Icon still available?
No. Riot tied the Unconquered Frontier Icon to 2018 (mission reward), and it does not normally bring back past event rewards or bundles.
