WETH Debt on Aave

You can borrow ETH on Aave in the form of WETH

Aave enabled you to borrow against your supplied (deposited) collateral. On Ethereum Mainnet, you can borrow ETH in the form of WETH (wrapped Ether). WETH is an ERC20 version of native ETH and 1 ETH is equal to 1 WETH.

Using SuperStaker, you are borrowing WETH against stETH collateral, and using that WETH to stake more ETH, with the resulting stETH also deposited in Aave.