REF is the governance token of Ref Finance. It is used to vote on changes to the protocol. Ref Finance also shares some of the trading fees with the holders of the token, similar to how SushiSwap does it.
The holders can stake their REF in an xREF pool that receives a share of the fees. Most of the trading fees are added to the liquidity pool, which lets the liquidity providers earn a compounding yield but 0.16% of each trade is used to reward the protocol. 3/4 of that protocol fe