You may need this basically for security reasons. When somebody installed this plugin (https://wappalyzer.com/download) on the browser, s/he can see all the frameworks and javascript libraries among other things. Wappalyzer uses json to specify what it should be looking for. Check this GitHub Repo to understand how it identifies Laravel (https://github.com/ElbertF/Wappalyzer/blob/master/share/apps.json). So, to hide Laravel from this plugin, you need to edit the Session Cookie Name in /app/config/session.php. Change it from laravel_session to your desire name e.g: yourapp_session. Hope this helps.
/*
|--------------------------------------------------------------------------
| Session Cookie Name
|--------------------------------------------------------------------------
|
| Here you may change the name of the cookie used to identify a session
| instance by ID. The name specified here will get used every time a
| new session cookie is created by the framework for every driver.
|
*/
//'cookie' => 'laravel_session',
'cookie' => 'yourapp_session',