Facebook 'recognized devices' - how did a device get on this in my settings?

I noticed a device 'Facebook for iphone' under 'recognised devices' in the security settings. Out of curiosity I read into how it might've got there as I didn't remember adding it. It seems it should only appear there if you use the login approval or login notification feature, and then click to recognize that device, both of which I've never done.
I'm a little worried that somehow someone else has done this..is there any other way my iphone could've been added to this list?
Does anyone else have their device recognized in this list but haven't asked for login notifications or approvals? I hope so!!
Your help would be greatly appreciated.
Asked Nov 30, 2013

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