She’s the ‘Down Judge,’ which is just under the Head Referee and Umpire. Down judges manage the chains, set the line of scrimmage, mark the spot where the play ends, and make line-of-scrimmage calls like false starts and offsides.
Sarah was just promoted to Down Judge last season. She previously served as a ‘Line Judge.’
Interesting Fact: The Down Judge was previously called the Head Linesman. The NFL’s officiating director says it was changed in 2017 to be gender neutral . . . but it wasn’t directly because of Sarah. He said they’d decided on making the change BEFORE she was promoted.