Where can I find the menu generator in Laravel?

Question

HTML

Good evening gentlemen, the problem is of the following kind.
I installed the admin panel and I'm trying to display the menu in view.
But something doesn't stick to me.
The standard function from the developers that outputs a list does not satisfy me, since I want to connect CSS to HTML.
The output from this function comes:
menu('main')

HtmlString {#619 ▼
  #html: """
    <ul>\n
    \n
        \n
        \n
        <li class="">\n
            <a href="http://rishat.kg/public/contact" target="_blank" style="">\n
                \n
                <span>Наши контакты</span>\n
            </a>\n
                </li>\n
        \n
        \n
        <li class="">\n
            <a href="http://rishat.kg/public/istoria-iuca" target="_self" style="">\n
                \n
                <span>О МУЦА</span>\n
            </a>\n
                </li>\n
    \n
    </ul>\n
    """
}

Therefore, I would like to customize it for myself, but I can’t find it in the code. I searched through the search for lines in a file in the Laravel project directory and swim in the wilds there, there is no result.
I searched in the database, I thought maybe HTML String is loaded from the database. Also unsuccessful.
The documentation has the ability to create your own template and menu output. But I seem to have a problem with the Menu class. Which, oddly enough, I don't have.
I'm trying to understand, do I need to create this class with handles? But there is no mention of this in the documentation.
It seems the same problem with visibility and setting APP_URL. But not exactly :) About which I asked a question here
And it seems to have fixed it, now everything works for me. :)
Documentation:
https://the-control-group.github.io/voyager/docs/v...
I see two solutions:
1) Somehow find a function that sends an HTMLstring to me in the view.
2) Write your view and a new class. (But this is too much for me, the bike should already be there)