nonrestrictive

Nonrestrictive describes something that adds information without limiting or defining what it modifies.

In grammar, a nonrestrictive clause provides extra detail that could be removed without changing the sentence's core meaning: My brother, who lives in Denver, is visiting uses commas to mark the clause as nonrestrictive—I have only one brother, so the clause merely adds information.

Compare restrictive clauses, which identify which one: The brother who lives in Denver is visiting implies I have multiple brothers.