This Cosmic Anomaly is the drone equivalent of a pirate faction sanctum, and like those sites it comes in two flavors.
This version has you arrive at a desolate, ruined starbase, where a cluster of 8 hybrid turret lookouts are arranged in a circle, with a single BC orbiting them.
Take out all Lookouts first, because a fresh wave of drones will spawn when the battlecruiser is destroyed. Additional waves arrive when certain battleships are destroyed. Most of the waves are 3-4 BS with 3-4 smaller ships in support, though one wave is HACs/cruisers with frigates.
This version has you warp into a base centered around four bunkers, with four more sets of bunkers arranged in a rectangle around them. At each corner of the base is a Lookout Sentry, three of them hybrid guns and one of them a type II Energy Neutralizer. In addition, each point has 1-2 BS plus 1-2 smaller ships (cruisers or frigates). The frigates will web and scramble, so the first thing you should do when you arrive is destroy the neutralizer while setting your drones on the frigates.
When you destroy all of the ships in one of these groups, it will trigger a fresh spawn of enemies, each new group consisting of 3-4 BS plus 3-4 cruiser/BC/HACs/frigs, so be careful with what you shoot in order to prevent being overwhelmed. At the end of these spawns, there is a final group that you destroy to finish the site.
Drones don't drop alloys anymore, they just give bounties now. There is a possibility with either type of horde to get a Sentient spawn during the final wave, which drops advanced drone components and gives T2 salvage. In addition, there is a chance for an escalation to the drone 10/10 complex. If you get one of those, FOR THE LOVE OF GOD AND ALL THAT'S HOLY SKIP IT.