I suspect this is what he's after. For whatever reason he thinks a significant number of Twitter devs did little if anything. Maybe he's even right about that,

I suspect this is what he's after. For whatever reason he thinks a significant number of Twitter devs did little if anything. Maybe he's even right about that, it's not exactly unheard of in big companies. But I don't think this is a particularly effective way to root those people out. It's also possible he's reassigning teams from the ground up, and this is his sorting method.