Helllo Janatikey,
Its your Facebook access token, which you received after the sucess of Facebook login. It will require to fetch the details based on the permission given to that app. Please have a look at this link, it will help you to undrstand the Facebook login integration without using Facebook SDK. And you will recieve the access token in the method success and you can use that access token to get your friend list, update facebook wall etc. Please check and let us know if it helps.
Thanks,
Himanshu Sharma