Contao\CoreBundle\Security\User\ContaoUserProvider::isBackendUsername PHP Method

Checks if the given username can be mapped to a back end user.

private isBackendUsername ( string $username ) : boolean
$username	string
return	boolean

    private function isBackendUsername($username)
    {
        return 'backend' === $username && $this->isBackendScope();
    }

ContaoUserProvider