What is AllTasksByContext

Hi all,

I have following lines in my .emacs

(require 'planner-multi)
(require 'planner-trunk)

(setq planner-multi-copy-tasks-to-page "[[AllTasksByProject][p]] 
[[AllTasksByContext][c]]")

When I create a new tasks a specify page info as: "freebsd @home"
where freebsd is a project and @home is a context

Then I create a new task for example with following page info: "project1 
@work"

After this I have two identical files in my plans dir: AllTasksByProject and 
AllTasksByContext.

There are questions:
 - why these files absolutly identical
 - should these files store the same info but with different sorting (or may 
be something else)
- what is [c] and [p] mean in the emacs config file

Thx