It can be useful to have help text explaining individual options within a RadioSelectInputWidget. There currently isn't a way to pass help text to an individual radio option in OOUI, so where help text is required, it must be added to the label manually.

The PHP version of the RadioSelectInputWidget creates a RadioInputWidget, nested inside a FieldLayout, for each of its options. FieldLayouts accept a 'help' config for adding a help text label. Hence, it would be possible to pass through the help text for each option.

However, the JavaScript version of RadioSelectInputWidget creates a RadioOptionWidget for each of its options, and this is not nested inside a FieldLayout. The RadioOptionWidget does not have a way to add help text.

One solution could be to be for the JS widget to nest RadioOptionWidgets inside FieldLayouts.