Source code for systems that have to refuse things. Each one ships as a running application with its evidence attached: the rules it implements, quoted from the material they came from, and the tests that hold them up. You get a starting point you can read, run and change — not a demo of a product you cannot open.
Standalone batch release and deviation control that keeps a batch from shipping while anything is still open.
Order-fulfilment source code for marketplaces where one customer order splits across multiple vendors.