There are times when making single sided boards that you may want to avoid multiple jumpers since some I.C.s. don't go just Pin 1 to Pin 1 etc.
This is not the best example, however, consider the simple crossover component on my finger tip (with no finger print).
If I.C. X pin 1 goes to I.C. Y pin 2 and I.C. X pin 2 goes to I.C. Y pin 1, the crossover could be placed in-between the two I.C.s to accomplish this.
I would solder the crossover component on the foil side, just like a SMD resistor would be soldered.
Therefore the crossover component on the foil side contains the jumper(s) within itself.
