The new version the Scrum guide states:
"Product Backlog refinement is the act of adding detail, estimates, and order to items in the Product Backlog. This is an ongoing process in which the Product Owner and the Development Team collaborate on the details of Product Backlog items. During Product Backlog refinement, items are reviewed and revised. The Scrum Team decides how and when refinement is done."
The previous 2011 version of the guide stated:
"Product Backlog refinement should involve the Development Team and the Product Owner."
The new version further states:
"The Product Owner is responsible for maximizing the value of the product and the work of the Development Team."
"The Product Owner is the sole person responsible for managing the Product Backlog."
Does it mean that the PO is no longer responsible or held accountable for the grooming activity? Is the development team responsible? Or both?