Why Pritunl ovpn profile can use any username to connect

I am newbie and wondering why a random username can connect the the VPN…

Details:
Pritunl Server v1.30.3157.70 28a970

  1. Generate one user
  2. Put the profile on a Ubuntu server
  3. Connect using OpenVPN with —auth-user-pass option to a file that contains the random username and the correct password

If missing any details pls ask… thank you

Each profile contains a certificate that is only valid for that Pritunl user. The server will only accept a password for the single sign-on username associated with that Pritunl user. The server will ignore the username provide and use the username associated with the user certificate.