5G E stands for 5G Evolution, which is a marketing term used by AT&T to describe their enhanced 4G LTE network. It is not a true 5G network, and the "E" stands for "evolution" rather than "enhanced". The 5G E network uses 4G LTE technologies like three-way carrier aggregation, 4x4 MIMO, and 256 QAM to make existing wireless networks faster. These are technologies that have already been in place on AT&Ts network and networks from other carriers like Verizon, Sprint, and T-Mobile. The peak download speed of 5GE is about 100 Mbps, and the average speed is about 20 Mbps. Therefore, if you see the 5G E icon on your phone, it means that you are connected to AT&Ts enhanced 4G LTE network, not a true 5G network.