While photos posted to reveal the existence of an NFC chip from NXP has seen identifying marks on many of the other components blurred, a portion of the text printed on the LTE modem is visible, confirming the board does indeed contain Qualcomm's MDM9625M as had been previously rumored.
The Qualcomm MDM9625M modem is a Category 4 LTE modem which means that it will support speeds of up to 150 Mbps. The modem in the iPhone 5s is a Category 3 modem which only supports speeds of up to 100 Mbps.
The new modem will allow for carrier aggregation to combine channels for more bandwidth. The companion chips to enable this feature have also been spotted on the logic board.
With the MDM9625, this carrier aggregation requires a pair of companion chips, a WTR1625L transceiver chip and a WFR1620 chip. These chips appear to be located on the opposite of the iPhone 6 logic board from the LTE modem itself.
So far the logic boards have also revealed an A8 processor, 1GB of RAM, a NFC chip, and 16GB of flash storage. It's also been used to assemble an iPhone 6 which actually powers on. You can watch that video here.
Apple is expected to unveil the iPhone 6 at its September 9th event. Make sure you follow iClarified on Twitter, Facebook, Google+, or RSS for updates.
[Possible WTR1625L in red and WFR1620 in blue]