What's the magic behind the ELPA?

Question

I use Aquamacs, and I use ELPA that installs files in ~/.emacs.d/elpa?

What's the magic behind this ELPA? I mean, without ELPA, I should download and install the packages in a specific directory, and add those two lines in .emacs.

(add-to-list 'load-path "PACKAGE_DIRECTORY")
(require 'PACKAGE)

But, with ELPA, I don't see anything added to .emacs or /Users/smcho/Library/Preferences/Aquamacs Emacs/{Preferences.el, customizations.el}. How is this possible?

Added

This is what I found with Aquamacs.

1. Aquamacs reads ~/Preference/Aquamacs Emacs/Preference, and it has "(add-to-list 'load-path kitfiles-dir)(require 'init)", which reads start kit.
2. The init.el of start kit has the "(require 'package)(package-initialize)"
3. ~/Library/Preferences/Aquamacs Emacs/aquamacs-emacs-starter-kit/vendor has the package.el

I guess the initialization files are not changed, but the package manager reads the ~/.emacs.d/elpd/* to initialize automatically, as I see *-autoloads.el in each of it.

Answer 1

You have a (require 'package) (package-initialize) pair somewhere in your initialization files. Package.el does the magic :)