g to the preceding rule, the provider specifically registered for the value
 passed as the appContext argument and for all (that is, null) layers shall be selected.
 <li>If no provider is selected according to the preceding rules, the provider specifically registered for the value
 passed as the layer argument and for all (that is, null) appContexts shall be selected.
 <li>If no provider is selected according to the preceding rules, the provider registered for all (that is, null)
 layers and for all (that i