AO3some

That comment is just meant to represent the rest of any userscript's code. Because it's wrapped in a closure, you can have your own reference to jQuery inside, and name it whatever you want (the conventional $ being preferable to "unsafeWindow.jQuery" for terseness/cleanliness) without reassigning $ in the global scope.

Does this make more sense?

(function($) {
    // 500 lines of code where you do all kinds of cool stuff
    // using jQuery, but referencing it as $ rather than unsafeWindow.jQuery
    $('body').addClass('sparkly');
})(unsafeWindow.jQuery)