They will be used by b2gpopulate. I considered using a type argument, in fact that was how I originally coded this, but the type is actually passed directly to the device storage API as a storage name. I wanted any consumer of gaiatest to specify the type it wants to delete, and allow gaiatest to translate that into the appropriate storage name. Although it would be a fairly simple pass-through for all of our cases here, I wanted to provide more assurance to consumers.