PlayStation Plus December 2020 free titles have been revealed by Sony, and includes three titles on PS4 and PS5 alongside a special bonus game on PS5: Bugsnax.
Those with a PlayStation Plus subscription will able to download the following games throughout December 2020:
Worms Rumble
Just Cause...
I want to say it's one to one, but in all honesty I'm a bit fuzzy there. I can recommend JoyFreak's sister site AdminIntel - Admin & Webmaster Resource where there are lots for people of varying degrees of expertise with development, you likely can get a far more precise answer there!