After upgrading my MKIII Nav unit to version 3-1/63, I noticed that I now have an additional feature called "Memo" in the SET menu option.

If I turn Memo on, a little icon appears on the Navigation screen, looking like a sound wave icon.

Then on every last minute of the hour, a warning chime sounds, announcing the start of the next hour.

Is this solely what the Memo function is meant to do?