Question about C7/8 and R8 on Grovve Lora E5

Hi all,
I’m working with Seed Grove Lora E5 module, for now I’d like to create my own board inspired by Grove module. I’ve looked the schematic pdf but I have a question.

On the PDF on the RFIO pin before the antenna we have 2 condensators and 1 resistor. C7 and C8 doesn’t have value, and R8 vamue is 0R. Why? There is a way to calcultate this ?