When developing an Android application, when you specify the tone number of the Beep sound with ToneGenerator, you can check what kind of sound is produced by which number.
The tone number buttons from 00 to 97 are lined up, and when you press the button, the corresponding beep sounds. The ringing time can be adjusted from 0 to 5000 ms every 10 ms by the slider at the top or manual input.

The number on the upper right of the screen shows the tone number you pressed.
As a hidden function, pressing it turns on the constant name display mode, and each time you press the tone number button, the constant name of Tone Generator will be displayed as a toast.
(It will be restored when the app is restarted)