Fedora Core 4 2.6.14-1.165_FC4 Source Code -- dumb question?

[William Case]

Hi;

I want to start exploring the internal source code of Fedora.  It has
come to that point for me in the Linux learning curve.  I want something
that is as close as possible to the binaries on my system.

I have found several download sites.  The Fedora site seems out of date;
I am not sure if the kernel.org's source is the same as mine.  Etc. etc.

Where should I get the right source.   I have a couple of kernel and
architecture manuals that I have already read. Any special suggestions
about how I should start digging in, gratefully received.

Regards Bill