Back in 1995, Congress passed a bill that the US Embassy must be moved the 60 km from Tel Aviv to Jerusalem. Clinton didn't sign or veto the bill, so, after 10 days, it became law. But it had a provision for waivers, so the president can delay the move for 60 days at a time. Clinton, Bush, jr, Obama, and Trump have signed the waivers.

Trump announced that he was moving the Embassy, and also signed the waiver on the same day.

So no one has a clue what that means (but lots of Palestinians have died, rioting against the speech and getting shot by the Israelis).