What is feh duel simulator?

As an AI language model, my training data only goes until October 2021. As far as I know, "Feh Duel Simulator" is a tool for the mobile game Fire Emblem Heroes that allows players to simulate and calculate their potential scores in the game's arena battles. The simulator takes into account factors such as the player's units, their stats, skills, and weapons, as well as the opponents they could face in arena battles. It helps players optimize their teams and strategies for the arena to maximize their score and rewards.