On the backside we find a lot more:

Samsung K3QF2F20EM-QGCF 2 GB LPDDR3 RAM, layered on top of the Qualcomm Snapdragon 801 MSM8974AB

Qualcomm WTR1625L RF Receiver (similar to iPhone 6)

RF Micro Device RF7389EU Multimode Multiband Power Amplifier Module

Qualcomm QFE1100 Envelope Tracking Power Management

Qualcomm PM8841 PMIC

Qualcomm WCD9320 Audio Codec

Qorvo RF1496A SP12T Antenna Switch