WBTC is a lending market on Spark (Ethereum), listed as Wrapped BTC. Depositors supply WBTC to the market and earn a variable interest rate paid by borrowers, who post collateral and are liquidated if their loan outgrows the market's limits. The rate floats with utilization — how much of the supplied WBTC is borrowed at the time — so the market is used to earn on an idle WBTC balance, or to borrow against collateral without selling it.
