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.

That's interesting. Here is more information https://sqlite.org/th3.html

The roots of SQLite are in defence industry projects of US Navy and General Dynamics. Seems like TH3 might be of interest for these sort of users.

One could assume also for Fossil.