So as I was looking through the source code in nag-menu-template.php to change the hyperlinks of each page listing in the main menu, I came across:
$args = apply_filters( 'wp_nav_menu_args', $args );
However, I can't find where this hook/tag is defined in, despite searching this on wordpress and other sites. There are couple other tags/hooks:
wp_nav_menu_objects, wp_nav_menu_items.. Can someone tell me what file these functions/tags/hooks are located in? Do they just lack documentation, or am I not fully comprehending Plugins and hooks?