Two site-wide initialization files, `site-load.el' and `site-init.el', are loaded into Emacs and then `dumped' if a `dumped' version of Emacs is created, as is most common. (Dumped copies of Emacs load more quickly. However, once a file is loaded and dumped, a
change to it does not lead to a change in Emacs unless you load it yourself or re-dump Emacs. *Note Building Emacs: (elisp)Building Emacs, and the `INSTALL' file.)