Tricks of the Wizards

Config.pm

Config.pm contains most of the configuration information as a giant string
The string is not parsed when you load the module
Instead, the FETCH method searches it for the configuration variable you asked for
Then it caches the result
FETCH also generates some of the configuration information dynamically
%Config is read-only:

        sub STORE  { die "\%Config::Config is read-only\n" }