Reserved key to identify the most specific menu link for a given path.
The value of this constant is a hash of the constant name. We use the hash so that the reserved key is over 32 characters in length and will not collide with allowed menu names:
sha1('MENU_PREFERRED_LINK') = 1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91
define('MENU_PREFERRED_LINK', '1cf698d64d1aa4b83907cf6ed55db3a7f8e92c91');