Which is not a feature of a user story?

In agile practices, particularly in the context of user stories, the features are typically defined by the INVEST criteria: Independent, Negotiable, Valuable, Estimable, Small, and Testable."Achievable"is not a standard feature of a user story. Instead, user stories should beNegotiable(they are not fixed, and details can be discussed),Estimable(it should be possible to estimate the effort required), andTestable(it should be possible to verify whether the story has been implemented correctly). Therefore, "Achievable" is not one of the features of a user story.