Line side tap lugs

There are three types of overhead distribution connectors. Mechanical connectors use hardware or similar mechanical methods to make contact points and to maintain connection integrity. Compression connectors use specific installation tools and/or dies to crimp the connector to the conductor with significant force making a permanent electrical joint or connections made by detonating a charge to ...The first pic is of a double tap off the main lugs to feed an adjacent 200 amp panel instead of a dedicated breaker in the main panel feeding the 200 amp sub. The 2nd pic is of the main panel wiring schematic. The lugs the aluminum cable are secured beneath look more like main breaker hold down screws to me than anything else. Am I