Wu said that he learned that recently @spark_ren asked "Why is it proposed that the CKB of RGB++ is BTC L2? It feels like it is essentially an indexer? What the client does to verify CSV is to verify the asset just like the indexer." CKB Lianchuang cipher replied: "RGB++ is a client verification protocol and an extension that introduces Turing complete programming to Bitcoin. The relevant RGB assets and state ownership are verified/verified by the Bitcoin main chain maintenance (Wu Shuo Note: RGB It is required that every state of each contract must be attached to a certain Bitcoin UTXO; and once this state is changed, this UTXO must be spent and the transaction that spends it must be confirmed by the blockchain), and CKB here It serves as the verification/layer of the script/contract (Wu Shuo Note: Although "Validation" and "Verified" do both involve verification, the former is an off-chain transaction that verifies the legality of RGB transactions, and the latter is attached to RGB assets. The main chain transaction spent on the state change of UTXO), although the client verification and indexer are essentially verification of the legality of new asset transactions, but because RGB assets are attached to UTXO, RGB only needs to verify the relevant historical branches corresponding to UTXO That’s it, without the need to scan and verify global transactions like an indexer, so it’s relatively lightweight.”