Using the tooltip argument you can add tooltips to your controls.
We recommend using descriptions instead of tooltips as descriptions are always visible while tooltips require the user to click the (i) icon next to the control in order to see the details.
Backwards-compatibility notice
Note: This argument was called help in versions < 2.2.
For backwards-compatibility purposes we’re keeping compatibility with the help argument but we advise you to use the tooltip argument instead for consistency.
If you use the help argument instead of tooltip you may see a PHP Notice in your error-log informing you you should change to tooltip