Facebook app?

[lucy24]

Can someone verify that this is the Facebook app? I found a cluster of them today:

94.191.186.abc - - [13/Jan/2015:08:21:16 -0800] "GET /ebooks/barrow/PointBarrow.html HTTP/1.1" 200 33139 "http://m.facebook.com" "Mozilla/5.0 (iPhone; CPU iPhone OS 8_1_2 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12B440 [FBAN/FBIOS;FBAV/21.0.0.25.14;FBBV/6017145;FBDV/iPhone5,2;FBMD/iPhone;FBSN/iPhone OS;FBSV/8.1.2;FBSS/2; FBCR/3DK;FBID/phone;FBLC/da_DK;FBOP/5]" 

194.239.236.abc - - [13/Jan/2015:08:24:31 -0800] "GET /ebooks/barrow/PointBarrow.html HTTP/1.1" 200 33139 "http://m.facebook.com" "Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_2 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) Mobile/11D257 [FBAN/FBIOS;FBAV/21.0.0.25.14;FBBV/6017145;FBDV/iPhone6,2;FBMD/iPhone;FBSN/iPhone OS;FBSV/7.1.2;FBSS/2; FBCR/3DK;FBID/phone;FBLC/da_DK;FBOP/5]" 

194.177.235.abc - - [13/Jan/2015:09:30:56 -0800] "GET /ebooks/barrow/PointBarrow.html HTTP/1.1" 200 33139 "http://m.facebook.com" "Mozilla/5.0 (iPhone; CPU iPhone OS 8_1_2 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12B440 [FBAN/FBIOS;FBAV/20.1.0.15.10;FBBV/5758778;FBDV/iPhone6,2;FBMD/iPhone;FBSN/iPhone OS;FBSV/8.1.2;FBSS/2; FBCR/TELEGRL;FBID/phone;FBLC/da_DK;FBOP/5]" 

The first part of the UA string-- up to the bracketed section-- is a standard iPhone.

(In case anyone wondered: One of the three is actually Greenland, not Denmark-- as was the desktop user who made the original FB post. They may not realize that in iOS 8, you'd get at least some of your material in Kalaallisut.)

[wilderness]

lucy,
I've half-a-dozen of similar iPhone OS; from various IP's, and after one visitor provided a popular link on FB to one of my pages.

Unfortunately, I've no clue what type of app it is.

[trintragula]

Prompted by some recent discussion I've been looking at the facebook app strings in the user agent.

I've seen four major variants on this so far:

IOS (on iphones and ipads):

Mozilla/5.0 (iPhone; CPU iPhone OS 8_1_2 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12B440 [FBAN/FBIOS;FBAV/20.1.0.15.10;FBBV/5758778;FBDV/iPhone6,2;FBMD/iPhone;FBSN/iPhone OS;FBSV/8.1.2;FBSS/2; FBCR/TELEGRL;FBID/phone;FBLC/da_DK;FBOP/5]

the app is described in a long suffix enclosed in square brackets, with sections separated by semicolons.

The four-letter codes beginning with FB appear to be named properties:
[
FBAN/FBIOS;
FBAV/20.1.0.15.10;
FBBV/5758778;
FBDV/iPhone6,2;
FBMD/iPhone;
FBSN/iPhone OS;
FBSV/8.1.2;
FBSS/2;
FBCR/TELEGRL;
FBID/phone;
FBLC/da_DK;
FBOP/5
]

My guesses about what the property names mean:
FBAN: FaceBook Application Name
FBAV: FaceBook Application Version
FBBV: FaceBook Build Version
FBDV: FaceBook Device Version
FBMD: FaceBook Major Device
FBSN: FaceBook System Name
FBSV: FaceBook System Version
FBSS: FaceBook System Something :)
FBCR: FaceBook CarrieR
FBID: FaceBook Identity of Device
FBLC: FaceBook Language Code
FBOP: FaceBook Other Parameters? I've no idea - looks like it might be a decimalised bit mask

Posible values I've seen in some of the fields (those in parens are regex patterns):

FBAN: (FBIOS|FB4A|MessengerForiOS)
FBAV: { many, many... }
FBBV: { many, many... }
FBDV: (iPhone|iPad)[0-9],[0-9]
FBMD: (iPhone|iPad)
FBSN: (iPhone OS)
FBSV: { matches the OS version earlier in the useragent string }
FBSS: ([1-3])
FBCR: { Sprint, Verizon, , AT&T, Three, vodaAU, 3Austria, Telstra, TELIA, OPTUS, U.S.Cellular, TFW, OrangeFrance }
FBID: (phone|tablet)
FBLC: { any language code of the form en_US - I've seen many }
FBOP: (1|5)

On android:

Mozilla/5.0 (Linux; Android 4.4.2; SCH-I535 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/30.0.0.0 Mobile Safari/537.36 [FBAN/FB4A;FBAV/20.0.0.25.15;]

[
FBAN/FB4A;
FBAV/20.0.0.25.15;
]

also:

Mozilla/5.0 (Linux; Android 4.4.4; XT1080 Build/SU6-7) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/33.0.0.0 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/30.0.0.19.17;]

[
FB_IAB/FB4A;
FBAV/30.0.0.19.17;
]


it's possible FB_IAB is replacing FBAN here in later versions.

On IOS (iPhones and ipads):

Mozilla/5.0 (iPhone; CPU iPhone OS 8_2 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12D508 [FBAN/MessengerForiOS;FBAV/25.0.0.4.14;FBBV/8936291;FBDV/iPhone5,3;FBMD/iPhone;FBSN/iPhone OS;FBSV/8.2;FBSS/2; FBCR/Verizon;FBID/phone;FBLC/en_US;FBOP/5]

[
FBAN/MessengerForiOS;
FBAV/25.0.0.4.14;
FBBV/8936291;
FBDV/iPhone5,3;
FBMD/iPhone;
FBSN/iPhone OS;
FBSV/8.2;
FBSS/2;
FBCR/Verizon;
FBID/phone;
FBLC/en_US;
FBOP/5
]

I've seen MessengerForiOS in two different versions and FBIOS with higher and lower version numbers, so I don't think it's a renamed app. It would seem to be two different ones.
MessengerforiOS is the variant @keyplyr recently showed coming from AWS, but I've also seen it coming directly from mobile carriers.
Since I don't use either facebook or a smartphone, I can't offer much more about this than the visits I get on my site.

[wilderness]

FWIW, I've had a denial in place for more than decade (no space after semi-colon), and over time have been required to add exceptions.
These UA's (FB portions) been getting denied, although they were valid.

I simply added an exception:

RewriteCond %{HTTP_USER_AGENT} !\[FB