What is bus isolation resistors
The resistors provide enough series resistance that whatever logic is connected to the right of your schematic can drive any of those lines easily to '1' or '0'. 

If said logic allows any of the lines to float (tristates the line), then the switch or jumper plus pulldown 10K resistor will allow the line to (fairly slowly) achieve a known logic level. If the switch is open (or the jumper is not populated) then the pulldown resistor gives a logic '0'. This is assuming CMOS logic, which tolerates high impedance pullup or pulldown resistors. 

This allows each line to do double duty- as a high-speed communication bus between multiple devices connected to the right of your schematic and as a low speed input of fixed or rarely changed configuration data. 

The reason the configuration inputs are lower speed is that the RC time constant of the pulldown resistors with stray and input capacitance is much higher than that of CMOS outputs when the latter are enabled.