Login Notifications are an opt-in security feature where alerts are sent to you each time your account is accessed from a new device to keep the bad guys out and keep you abreast of suspicious activity so you can quickly take action to correct it.
Facebook, from today started showing additional information in it’s email login notification.
The notification mentions the Operating System, Browser, Location and IP address along with the previously available info such as Device name, Date and Time of login, when the security feature was first introduced in 2010.
To turn on Login Notifications:
1] Go to your Security Settings page ( > Account Security > Security)
2] Click on the Login Notifications section
3] Check the box next to the type of alerts you’d like to receive and save your changes
You can also receive text message alerts by adding a mobile number to your account.