Product backlogs are a weird bunch. They contain everything from high-level dreams to year-old ideas over technical tasks and bugs. They carry the stakeholders' expectations and developers' ambitions while also being the team's to-do list. It's a mixed bag.
I jumped on this super fast! Dead documents and full backlogs are the bane of every team I work on and with.
Same for my teams! It's what prevents us from doing our best work.