It was extended through June 2022 but as you've probably noticed, that's behind us.
Practically speaking, I wonder what happens when a US citizen shows up in the US with an expired US passport. Does he get deported?
You won't get deported, but obviously you need to arrive to the border..... So by land you will be allowed entry, but by air the airlines won't allow you to board
A shame as before the published waiver it was an "un-official" waiver, but good luck trying it now as the "published" waiver was ended