One of the primary jobs of Pyramid is to find and invoke a view
callable when a request reaches your application. View callables
are bits of code which do something interesting in response to a
request made to your application. A Pyramid view callable is
often referred to in conversational shorthand as a view. In this
documentation, however, we need to use less ambiguous
terminology because there are significant differences between
view configuration, the code that implements a view callable,
and the process of view lookup. The URL Dispatch, and Traversal
chapters describes how, using information from the request, a
context resource is computed. But the context resource itself
isn’t very useful without an associated view callable. A view
callable returns a response to a user, often using the context
resource to do so. The job of actually locating and invoking the
“best” view callable is the job of the view lookup subsystem.
The view lookup subsystem compares the resource supplied by
resource location and info