According to Wu, BTCEden, launched by GeekWeb3 and the Chinese community of BitVM, proposed to analyze the risk of Bitcoin expansion network from six dimensions: withdrawal bridge, state verification, censorship resistance, data release (DA), reorganization resistance, and forced asset escape. Taking Bitcoin L2 Rootstock and Liquid, which are listed by Bitcoin Magazine as meeting its definition, as an example, the Rootstock withdrawal bridge is related to PowPeg, and there is a trust assumption on specific nodes; through Operation Codes merged mining, Bitcoin miners are also Rootstock miners, and will reject invalid blocks; using Optimistic Merged Mining, the block header data is verified on the chain; data is released off the chain; there is no forced asset escape mechanism. Liquid is a federated side chain of Bitcoin, using a multi-signature bridge, off-chain state verification, and using the functions and governance mechanisms of the federation for censorship resistance, reorganization resistance, and data release, and there is no forced asset escape mechanism.