Official document address
https://ui-router.github.io/n...$stateProvider

Explanation about the data of $stateProvider.state

Arbitrary data object, useful for custom configuration. The parent state's data is prototypally inherited. In other words, adding a data property to a state adds it to the entire subtree via prototypal inheritance.

Machine translation

Arbitrary data object, suitable for custom configuration. The data of the parent state is prototypically inherited. In other words, adding a data attribute to a state adds it to the entire subtree via prototypal inheritance.

Simply put, it is a custom configuration of routing. You can get this value as a parameter in the controller

function Ctrl($state){
    console.log($state.current.data.status) // outputs "1";
}