License game engine?

Anyone know the criteria to make “License game engine” research available in the R&D lab? I showed up in one game, but I’m not sure what I did, and it’s not there now.

The Licence Game Engine option allows you to add a SDK to the next engine you build. This will mean that you get some cash each month (at the same time you pay your staff’s wages) from the engine being licenced to other studios.

That isn’t what he asked…