The Definition of Ready isn't a practice defined in the Scrum Guide. However, some teams have created a checklist while refining the PBIs, to ensure that the PBIs entering the Sprint Planning are well refined, clear and free from dependencies. Caution must be excercised to avoid the definition of ready from becoming an extensive list that eventually hinders the emergence of right details later. The Scrum Guide hints about readiness of PBIs, however doesn't prescribe any such DOR criteria: