An indenture may include a clause providing the events of default and the terms and conditions upon which such default and its consequences may be waived. An indenture may include a clause designating the rights, limitations, power, and duties arising upon breach by the commission or department of any of the covenants, conditions, or obligations contained in any indenture; provided, that no indenture shall limit or restrict the rights granted to bondholders by Article 7 (commencing with Section 67620).