The fact is that I don't think it is well specified.
My feed reader will update the URL if the ending feed has a self URL that points at itself. But I don't think that is very common. In theory a permanent redirect should also be a signal to update the URL.
My feed reader will update the URL if the ending feed has a self URL that points at itself. But I don't think that is very common. In theory a permanent redirect should also be a signal to update the URL.