Who is the content authority for an Agile Team?

According to SAFe 6.0, “The Product Owner is the content authority for the team backlog. They are responsible for defining Stories and prioritizing the team backlog to streamline the execution of program priorities while maintaining the conceptual and technical integrity of the Features or components the team is responsible for.” The Scrum Master/Team Coach facilitates team events and removes impediments, but does not own content decisions. Product Manager and System Architect provide input and guidance but are not the content authority at the team level.
Reference: SAFe 6.0, “Product Owner” article SPC 6.0 Practice Guide, “Establishing Team and Technical Agility” module ===========