Hi,
I'm curious why the C116 to GND is needed. What might be it's function?

 

No one knows except the person who specified it.

 

Is this a guessing game? A few more clues might be helpful.
What is it?
What is the rest of the circuit?
What does it do?
If we know those answers and any other relevant information you can give, we might be able to guess why the communication clock line is connected to ground through a capacitor.
Regards,
Keith

 

It is acting as a high-frequency filter.

 

It is not a good idea to load an output with a capacitor.