Hi 3v0,
please excuse me. I have some trouble understanding what the word 'jumper' means. On your layout I could detect just two of them. There are two more red traces, but they are supposedly not called jumpers, are they?
The RED lines are all jumpers. In this case wires soldered to the top side of the board.
May be I misunderstood the explanation of the term as given by Torben, but I assumed a jumper is something straight on a PCB.
He gave a very broad definition of jumper. In this case (and most PCB related) wires (not traces) used to jump over traces are jumpers. If you have two pins on a header and you connect them together with a shorting block that is often called a jumper too, but it may be best to think of it as a shorting block. In my layout there are 6 solder jumpers. These act like the shorting block but there are no pins. Just a small gap that you can bridge with solder.
How should a foreigner learn good English if everybody has his own interpretation of technical terms?
Hans