They announced developer productivity analytics in the same keynote as they announced codespaces. It's not just coming, it's here!
Funny enough, after introducing the analytics stuff, they started the next section by showing that the more code you write the more security vulnerabilities you have.
Which is it, Github? Do I want to stay on top of your SLOC leaderboards so my manager doesn't fire me? Or does writing the most lines mean I introduced the most vulnerabilities so my manager should fire me? The answer depends on which product github is trying to sell you at that very moment.