A lot has been said about an official Facebook phone, including Mark Zuckerberg's claim that a "phone just doesn't make any sense". However, Pocket-lint can exclusively reveal that a Facebook phone is in development, and it's the mysterious device that has recently popped up in a benchmark test, the HTC Opera UL.Our very reliable source has confirmed that the HTC Opera UL (yes, that's the working title, not "HTC Operaul") is an "OEM product" for the social networking giant. And, so we were left in no doubt, they added: "It is the Facebook phone, made for Facebook."However, although we're not entirely sure what it means exactly, our source also informed us that "apparently it's been delayed". As we didn't know when it was due to hit in the first place, it's hard to guess what that delay may entail.Either way, this solves two mysteries. First, the rumours that HTC is manufacturing an official Facebook phone are correct. And second, the enigmatic HTC Opera UL is real and it will be Zuckerberg and his company's first foray into the smartphone hardware market.Thanks to the NenaMark 2 benchmark test, we even know that it will sport a 1.4GHz processor (although we don't exactly know the chip itself, you can bet it'll be dual-core). We also know that the graphics processor will be the\u00a0Qualcomm\u00a0Adreno 305, that its display will be HD (1280 x 720), and that, at the moment, it is run on Android 4.1.1 (Jelly Bean).What's also the betting that it will be blue?