BVLOS (Beyond Visual Line Of Sight) is an operation in which the remote pilot cannot see the drone directly — it flies behind obstacles, over the horizon, or simply further than the eye can resolve. Flying purely by the camera feed or a map is also BVLOS.
In the open category BVLOS is not allowed in any subcategory. Such flights require the specific category — either an individual operational authorisation from the CAA or compliance with the STS-02 standard scenario. It is one of the clearest boundary lines of the open category.