Here is a recording of a shiur I gave on the Unetane Tokef prayer, recited by Ashkenazim on both Rosh Hashana and Yom Kippur. It is mainly about the provenance of the prayer, how the story is first recorded by the Or Zarua, who cites Rabbi Ephraim of Bonn, who reportedly said that Rabbi Kalonymous ben Meshulam learned the prayer in a dream from Rabbi Amnon of Mainz.

I gave it a year after the October 7 terror attacks.