Have you open-sourced any software or heard about someone that has?

Open-source softwares have decent advantages and some disadvantages. I'm doing some research to better understand how the industry works, from a vendor perspective.

Have you open-sourced any existing software or heard about someone that has? What I mean is, an organization or individual that had already had software and moved it to the "public" as growth, marketing strategy, and to improve the software collectively.

Thanks in advance for sharing your thoughts!