Maybe not what you meant, but I immediately thought of SaaS. Or various companies&#x27; policies of open sourcing non-core software.<p>Both of those are along the lines of &quot;I need code to do this thing, but I don&#x27;t want to be the (sole) maintainer.&quot;<p>You <i>could</i> write your own language, IDE, OS, build system, source control, networking library, logging library, shopping cart, payment processor, etc.