The two resistors (R10 and R11) provide a voltage that the processor uses to detect when the motor is stalled.
When running normally, the voltage at the junction of R10 and R11 will be around half the supply voltage. Probably have to subtract voltage drops across the transistors from that.
When the motor stalls, it becomes basically a short circuit. The voltage at R10 and R11 will drop.
The processor is probably using an ADC to monitor the voltage. The engineers might also have been real tricky and arranged it so that they could use a digit input to detect a stall. They could jigger it so that the normal operating voltage is above the level for "high" on the processor, and below the level for "low" when the motor stalls.
C1 smooths the stall detect signal. It forms a low pass filter together with R10 and R11. The cutoff will probably be way lower than the PWM frequency. It also cleans up "trash" from the motor brushes.
I'm not going to try to guess the real voltages present at R10 and R11. That's going to depend on the transistors, the power supply, the motor, and how "hard" the processor is driving the transistors (whether they are in saturation or not.)
Not everything you'd need to calculate is there, and I'm not sure I could do it anyway.
Low voltage when stalled, somewhat higher when running normally.