Does Laravel 5 comes with Bootstrap framework?

I'm learning Bootstrap and Laravel. Right now, I'm creating a navigation bar using Bootstrap CSS and got stuck after I found a bootstrap.min.css and other CSS files and Bootstrap JS in my Laravel project inside the Laravel's folders. I'm not using Laravel's PHP yet, just playing with HTML and CSS.
By the way, that bootstrap.min.css is a little bit outdated as I've used a downloaded bootstrap.css from its website which is higher version.

I'm stuck because I wanted to create a sign-in form inside the navbar using the downloaded bootstrap.css placed inside the public folder, same as my HTML file. However, Laravel has built-in authentication handling etc. I though that maybe Laravel has to use it's own styling when creating an authentication.

Does Laravel really comes with pre-installed Bootstrap framework?
If so, should I continue creating a sign-in form and then I'll be able to use it with PHP? Or the HTML and CSS are being created by Laravel when working with its authentication?

via Chebli Mohamed