DefiLlama founder 0xngmi said in a social media post that to be honest, almost every cross-chain bridge (including WBTC) will provide proof of reserve so that users can check whether the issued tokens have enough support. However, Coinbase did not do this and cbBTC is far below par in terms of transparency. This is also the reason why we have not listed it on Defillama yet, as we cannot verify its TVL (Total Lock-up Amount). If we do not list those other cross-chain bridge projects that cannot verify TVL, then we will not make an exception for Coinbase either. We follow the same rules for all projects.