I'm not sure about the odds of "natural" data leaks, but if you use an EMP Bomb to create a Data leak on a module. One of the data leaks created from that Bomb, is guaranteed to give you the Blueprint (provided you have the research).

So you can use EMPs to increase the odds of getting the Blueprints. You're still required to have the research, but with creative game starts you can start off with the HQ and the necessary research complete if you aren't interested in doing those again.

Good to know. Though a mod that allows the EMP a chance to get a blueprint when you don't have the research would be nice.