Layers 3 (L3) are essential for decentralized applications (Dapps), focused on secure transactions supported by layer 2. Although they may lose some decentralization due to their high customization, they prioritize the security and speed of transactions. Every transaction on an L3 is mirrored on the L2 to ensure security and verification. Smart contracts and bridges are key components of L3, facilitating transactions and interoperability between blockchains.