What does it mean to start an open source project internal to an organization? Does that make any sense?
Many large organizations have very large systems within them, systems which are mission critical to the delivery of their business model. These systems are often bottlenecks for development as, in some fashion, they cannot be avoided and some development work is needed to complete any enterprise scale capability. They limit the change available to an organization.
What if there were a way to unlock the capacity limit on these systems? There is, open source the project.
If you open source a project internal to a company you are opening up the codebase for anyone in the company to work on. Instead of supplying a dedicated development team, you now need a dedicated team of system stewards, people that ensure the stability of the system and that the code being added meets the criteria of the project’s sponsors.
You can now do this fairly easily with Git based source control, where anyone in the company could write a module or patch and submit a pull request. The stewards review the pull request and whether the code takes them in the direction of their roadmap for the project and potentially accept the request into the main repo.
If done correctly you’ve opened up the system to the teams with the greatest need, while still maintaining control over the system and its direction. If done incorrectly you’ll probably have the biggest mess of your life. To push an entire enterprise forward at higher velocity the risk may be worth it.