http://msdn.microsoft.com/en-us/library/bb386417(v=vs.100).aspx
There's a saying——
The Application class is instantiated in the browser when the page contains a ScriptManager control. The Application class resembles the Page server control, which derives from the Control class, but provides additional functionality for raising server events. Similarly, the Application class derives from the Sys.Component class, but raises client life-cycle events that you can handle.
Notice the "Application" underlined and bold one:
I know they aren't the same，but what's the first "Application"（underlined）？I don't see it anywhere……Does it exist in the global.asax？Or an HttpModule？Something else？