访问时,websile加载的文件是什么?

I'm trying to fix some problems in a company's website but I dont know where is the main file of the website. Inside public_html folder there isn't a index.html file (or any other .html) only a index.php (that I will show below) and a lot of folders. I want to do a simple change in the main website index.html (or the .html that the website loads when u access). How can I find it?

This is the index.php:

<?php

/**
 * Laravel - A PHP Framework For Web Artisans
 *
 * @package  Laravel
 * @author   Taylor Otwell <taylor@laravel.com>
 */

$uri = urldecode(
    parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH)
);

// This file allows us to emulate Apache's "mod_rewrite" functionality from the
// built-in PHP web server. This provides a convenient way to test a Laravel
// application without having installed a "real" web server software here.
if ($uri !== '/' && file_exists(__DIR__.'/public'.$uri)) {
    return false;
}

require_once __DIR__.'/public/index.php';

If you are using laravel version const VERSION = '5.4.36'; then you can get the main file

public_html/routes/web.php

Route::get('/', function () {
return view('welcome');

});

check the / calling to where

Laravel have it's index inside public folder: public/index.php