According to @alice_und_bob, debate in the Ethereum community over the precise definition of Layer-2s is intensifying, drawing attention to how rollups are classified. Source: Twitter/@alice_und_bob, Aug 11, 2025. For traders, classification frameworks such as L2BEAT’s distinguish rollups versus validiums and track critical factors like data availability, upgrade keys, and proof systems, which are directly relevant for evaluating protocol risk. Source: L2BEAT Risk Framework and Project Listings. Ethereum’s rollup-centric roadmap states that rollups inherit Ethereum security when data is posted on-chain, while validium-style systems rely on external data availability assumptions, affecting security profiles and trust models. Source: Ethereum Foundation, rollup-centric roadmap. Key L2 tokens tied to distinct designs include Arbitrum (ARB) and Optimism (OP) as optimistic rollups, and Starknet (STRK) as a ZK rollup using STARK validity proofs, which traders can evaluate using the above frameworks. Source: Arbitrum Docs; Optimism Docs; Starknet Docs. Monitoring changes in L2 project maturity stages and governance disclosures can inform risk management and event-driven strategies in L2 tokens. Source: L2BEAT Rollup Maturity Model; official project announcements.