[crispyambulance]

tldr; for those who didn't bother to look for "an explanation" of why the wires were soldered directly to the pins of the IC instead of THE BREAK-OUT BOARD...

  > Now, you're probably thinking to yourself: "Why would you not just solder to the nice, big, widely spaced holes for the pin headers?", which is a fair question. I suppose this the one place I opted for a little less jank. You see, differential pairs actually require the length of wires and signal traces on a PCB to be carefully controlled. In theory, if the plus wire was a little longer than the minus wire, the two signals would arrive at the chip at very slightly different times. That would mess up the signal integrity, and maybe even prevent the device from working. All of that said, I'm almost certain that this wasn't required at all.

[tomn]

This could end up being worse from a signal-integrity point-of-view, as now both of those traces have a stub (of different lengths!), which will comb-filter the signal.

If you wanted to be fancy, it would have been better to lift those two pins, or to cut the traces.

All this is completely unnecessary given the speeds involved (12Mbit/s) and possible skew or stub lengths, which they acknowledge.