Welcome to the green zone. On third downs, see just how far players will have to go at any point during the play to get a first down. pic.twitter.com/cCLdkdLjls

You didn't even know that you needed a "Green Zone" to watch NFL games, did you! pic.twitter.com/1JBcNkmP7X

Basically, the Green Zone was intended to highlight the distance needed on third down to reach the first-down marker. And by that, NBC made the surface a darker shade of green as it led to the already-existing yellow line. If that seemed unnecessary, you weren't alone.