Yes No Input Type - Alekseon/magento2-widget-forms GitHub Wiki
Input with options Yes/No. This field cannot be empty, it always has value Yes or No.
If You want to have optional field "yes/no" then You should use Dropdown Input Type.
Admin Edit Form view
Frontend Widget Form view
Select Input Block Type
Radio Input Block Type
Checkbox Input Block Type
Default Value
It is possible to choose default selected value in field Advanced Settings.
More about Default Values
Example of use
This Input type can be used to create Agree to the Terms checkbox.
Select Checkbox as Input Block Type
Set field as Is Required
Put "I Agree to the Terms of Service" as field label