the microprocessors will run at 3v, the LED's probably at 12v so it has a couple voltage regulators in it; 48v is required to run dc through such small ethernet cables.. dropping the voltage down to its useable levels is trivial and wont generate much excess heat.. i doubt that module gets anything other than warm; its the sealed IP65 container with high power LED lamps that causes the heat buildup.
first reason I think they moved it out was they needed the space in the housing for more circuitry; power regulation tends to take up alot of valuable space and needs to be well isolated from sensitive electronics as they tend to be noisy from an RF perspective which causes problem with precise signal measurement... could of been a noise issue and this was the easiest way to resolve it.
it is poor design, reeks of being a cheap fix.. easier to do this then make a new housing format.. but thats china engineering for you.. why not only an ethernet port in the base of the bullet with a little rubber boot to keep it dry.. leme worry about the wires.. no one is using the 12v ports anyhow, poe injectors are cheap in china they could just include one in retail box units.. but that makes too much sence; everyone obviously has a power outlet near the other end of the ethernet cable.. On the plus side if they made replacement power boards it would be much easier to fix dead units.
all this circuitry can handle high heat; it was all cooked at 265c for a short time in an oven when it was made.. all the components have to be able to survive that for at least a few moments until the solder becomes molten. Obviously most components wont run in spec at half those temps; but you dont see that unless there is very poor cooling.
