"CentOS and MariaDB come to mind as two possible examples, that started as a means not to pay for the original projects." It is a stretch to even call CentOS a

"CentOS and MariaDB come to mind as two possible examples, that started as a means not to pay for the original projects." It is a stretch to even call CentOS a fork, and it is even more of a stretch to claim that Red Hat asks for donations. Red Hat charges for services, which include things like: 1. Maintaining binary packages so you do not have to try to track down dependencies by hand or subscribe to ten thousand mailing lists just to make sure your software is up to date. 2. Taking action when you file bug reports (how much you pay determines how fast that action is taken). 3. Sending people to your data center to help you get everything configured. 4. Get official ratings e.g. EAL4+, for those people who need their software to have such ratings.