13. What does "Required" stand for?
b. Not mandatory
The Required field parameter is not a mandatory but an advisory property. In other words, it is different from "NOT NULL" definition of the RDBMS world. Its purpose is to let the creation of validation rules treat all "Required" fields at once. Such validation expression is not available yet but will be exposed in coming versions. The advantage of this approach is when your validation logic is changed and you decide the field should or should not participate in the validation you simply change the value of "Required". Otherwise every validation expression should be changed manually.