How to Access Script Tags in Header

If done right there should be a callback hooked to wp_enqueue_scripts which has either wp_enqueue_script or both wp_register_script and wp_enqueue_script in it. Something like the following from the Codex:

function themeslug_enqueue_script() {
    wp_enqueue_script( 'my-js', 'filename.js', false );
}
add_action( 'wp_enqueue_scripts', 'themeslug_enqueue_script' );

You will need to find that callback function in your theme or in one of your plugins. You should be able to narrow things down by disabling plugins one by one, and by switching themes to a default theme like Twenty Twelve. Once you find it it should be obvious how to change the path.

If not done right, I have no way to guess what was done or how to alter it.