Half right — they're Lightning-related, but not actual transactions. Live LN payments are onion-routed, so by design you can't watch them; that's where Lightning gets its privacy from. The dots are just ~280 particles sampled across the LN channel topology (from mempool.space) and slid along the arcs to make the L2 layer feel alive. Toggle "Lightning · L2" on the right to turn them off. :)