This is a widget to display beat time, a measurement of time introduced by the Swatch corporation. Beat time divides a day into 1000 time units called 'beats' and is displayed as @DDD where DDD is 000 to 999. Beat time doesn't observe time zones or daylight savings time so it's the same no matter where you are located.

To use, just download the app and install the beat time widget just like any other widget on your platform.

You can read more about beat time at:
https://en.wikipedia.org/wiki/Swatch_Internet_Time