Re: Documentation on default.el vs site-start.el

[Richard M. Stallman]

    `C-h v site-run-file' also says that it is customizable, but that
    seems pointless: by the time the customization is done (whether in
    custom-file, .emacs, or default.el) the default site-run-file has
    already been loaded.

The doc string says this:

    This variable is defined for customization so as to make
    it visible in the relevant context.  However, actually customizing it
    is not allowed, since it would not work anyway.  The only way to set
    this variable usefully is to set it while building and dumping Emacs."