What are people's definitions of an "L3"?

Particularly, is it an architectural classification (whether or not there's some kind of intermediary between it and L1), or a security classification (can the attacker steal? can they freeze funds? can they steal/freeze but only at high cost?)

I like your old argument that it’s a kind of DSL/accelerator for specific vertical classes, not a leverage layer. Seems like the emerging autonomous worlds/dark forest infrastructure kinda fits the model for gaming. 

Though I think there may be a cache levels type argument to be made…they even use L1-3 terminology