c8fee158_pl____h_selectBooleanCheckbox___Description
[Name] requiredMessage [Type] String [Supports EL?] Yes [Description] 
Text to be displayed to the user as an error message when this component is marked as "required" but no input data is present during a postback (ie the user left the required field blank).
Apache MyFaces JSF-2.0 Core Impl - <h:selectBooleanCheckbox>