When i type in my browser: http://grav.xxxxxxxxx.pl/admin/config/site i have access to Configuration Site without login (after logout), i can read admin -email ,serwer data, settings of page, isn’t this a fatal error of Grav? 
Hmm… we recently changed the routes for those (1.0.7 I think) and it seems the security access checks were not updated. I have created an issue for this and we will get that sorted ASAP!
Thanks for finding this!
Ok, fixed and released 1.0.7 of Admin to address this. Thanks again.