How to stop jQuery.migrate manually

jQuery Migrate is nothing but a dependency of the jQuery script in WordPress, so one can simply remove that dependency.

The code for that is pretty straightforward:

function dequeue_jquery_migrate( $scripts ) {
    if ( ! is_admin() && ! empty( $scripts->registered['jquery'] ) ) {
        $scripts->registered['jquery']->deps = array_diff(
            $scripts->registered['jquery']->deps,
            [ 'jquery-migrate' ]
        );
    }
}
add_action( 'wp_default_scripts', 'dequeue_jquery_migrate' );

This will prevent the jQuery Migrate script from being loaded on the front end while keeping the jQuery script itself intact. It’s still being loaded in the admin to not break anything there.

In case you don’t want to put this in your own plugin or theme, you can use a plugin like jQuery Light that does this for you.