A Product Backlog item is an item of the Product Backlog. The first Product Backlog items should be described by the acronym INVEST: Independent, Negotiable, Valuable, Estimable, Small and Testable. Product backlog items can be functions or features, software errors as defects or bugs, technical work as infrastructure tasks, CI/CD tasks, deployment pipeline and others or knowledge enrichment experiments. The Product Backlog item can be described as a Theme, Epic or user story. A user story is described via a template: As a (customer, user, role (Who)), I want (goal, function, requirement (What)) so that / with it (benefit or reason (Why)).