It's still SQLite, they just need to make money: https://sqlite.org/prosupport.html

Edit: also this:

> TH3 Testing Support. The TH3 test harness is an aviation-grade test suite for SQLite. SQLite developers can run TH3 on specialized hardware and/or using specialized compile-time options, according to customer specification, either remotely or on customer premises. Pricing for this services is on a case-by-case basis depending on requirements.

One could assume also for Fossil.