My experience on Monday afternoon.
1--Arrive at Lufthansa counter to check in for flight. Show passport. Show your Covid test result (negative) from prior 3 days. (Be sure to get it back.) Get your boarding pass. (1b: If you are checking a bag, do that thing.) Now sign an "attestation" that you have received the very Covid test you just presented or that you are recovered from Covid. Take this document and put it in your purse. No one ever looks at it again. Walk.
2--Go through security. Walk.
3--Go through passport control. Look for a bank of machines under the sign "Automated Passport Control." If you have a US passport, you can use these machines. Scan your passport (insert in opening as shown and hold it still), walk through gate; pose for face scan; walk through gate to the passport agent and get your stamp. Entire thing takes 30 seconds. Eat and buy stuff (if you have time). Walk.
4--Somewhere on the way to the gate but before arriving at it, go through another Document Check. Show passport, boarding pass, and Covid test result again. (This stop was exclusively for passengers headed to Chicago or Boston. I don't know if there are other secondary doc checks.) Walk to gate.
DO allow extra time and bring your patience. There may be a line at any step.
DO NOT have a massive glass of Chardonnay between steps 3 and 4.