[comprev]

Some projects have varying licenses to extend their open source product beyond a bare bones system. Some companies pick "open core" license models which lock enterprise features behind a paywall.

For example a collaborative software text editor might require connections to a central database for synchronising the various users. The code to handle these connections might not be available, or at least heavily restricted through licensing from using in a business environment.

The SaaS company makes money by providing the infrastructure to allow users to actually collaborate with others. Until then it's simply a stand alone desktop text editor.

Alternatively the company may offer basic collaborative features which only support one 3rd party auth provider and synchronise via the public internet.

A customer might want on-prem networking only and Active Directory auth, and will pay for these features.