Help reverse engineering RCWL-0516 microwave proximity detector module
R-CDS (parallel to R15) is part of the voltage divider for the photo resistor (LDR). 
When it's bright, the LDR pulls the CDS line below 0.7V, disabling the trigger output (pin 9, VC). Thus, the brightness sensitivity can be adjusted with R-CDS. Populating R-CDS means enabling the trigger at brighter environment; the lower R-CDS, the brighter it has to be to disable the trigger. CDS can also pulled low from the pin header to disable triggering.

Also, pin 1 ("A") might be an input as in BISS0001 to enable re-triggering, tied to high on that board.

C-TM (in parallel to C2=10nF) is connected to pin 4, RC1, and seems to increase the trigger pulse width (might be a more clear wording than "repeat trigger time").
Haven't tried any of those though.

BTW, I've seen a video where someone powered the module with 3.3V on that 3.3V pin, VIN not connected, working fine. My guess is that the IC actually works with 3.3V and just has an internal 100mA 3.3V regulator (VIN->3.3) for ease of operation, meaning that pin 11 is VDD (same as BLISS0001). So the IC could be powered by 3.3V or 4+V - very convenient.