What is USDe backed by?

Could you please elaborate on the underlying assets supporting USDe? I'm curious about the collateralization mechanism behind this stablecoin. Is it primarily backed by fiat currencies, other cryptocurrencies, or perhaps a combination of both? Additionally, what measures are taken to ensure the stability and liquidity of USDe? Understanding its backing and the mechanisms employed for its maintenance would greatly assist in assessing its overall reliability and trustworthiness in the crypto finance landscape.