This pipeline makes it easy to add JavaScript code which will be inserted into every public and private page (which uses the tag #INSERT_HEAD).
It receives and returns an array that contains the paths (these paths will be completed by the function find_in_path()) of the files to be inserted:
$scripts = pipeline('jquery_plugins', array(
'javascript/jquery.js',
'javascript/jquery.form.js',
'javascript/ajaxCallback.js'
));