On Fridays and other important religious days it can house 8,000 worshippers under the tent-like stone roof of its Grand Hall.
Fridays are known to be important religious days.
It makes sense, then, for a browser that can find both internal and external documents to be an integral part of the system--unless, that is, you regard browsers and operating systems as still basically different things, and view Microsoft as practicing vertical foreclosure under the guise of product enhancement.