nsIApplicationCacheChannel in Firefox 3.6a1pre

 When true, the channel will choose an application cache if one
 was not explicitly provided and none is available from the
 notification callbacks.  Default value is false.

 This attribute will not be transferred through a redirect.

 NS_ERROR_ALREADY_OPENED will be thrown if set after AsyncOpen()
 is called.

 When true, the channel will ask its notification callbacks for
 an application cache if one is not explicitly provided.  Default
 value is true.

 NS_ERROR_ALREADY_OPENED will be thrown if set after AsyncOpen()
 is called.

 TRUE when the resource came from the application cache. This
 might be false even there is assigned an application cache
 e.g. in case of fallback of load of an entry matching bypass
 namespace.