The foldout menu consists of 2 files:

foldout.jsJavaScript to fold/unfold the menu items.

foldoutmenu.php2 small PHP functions. One which loads the javascript file, and creates aregister value, containing a list of pageids for all the pages which has sub items.And another which creates the initializing javascript code.

To use this extension, you just have to include the PHP file somewhere in your typoscript setup (similar to when using TMENU_LAYERS/GMENU_LAYERS), like this:

includeLibs.foldoutmenu = typo3conf/ext/foldoutmenu/foldoutmenu.php

Or if you have installed the extension as global instead of local:

includeLibs.foldoutmenu = typo3/ext/foldoutmenu/foldoutmenu.php