[AlexErrant]

The test suite is (partially) proprietary. Good luck maintaining a fork for a DB without tests.

https://www.sqlite.org/th3.html see bottom

[oneplane]

You can buy a license, and maintain your public fork while also letting everyone know you validated your fork with the same TH3 as the origin version. You just won't be able to show people your TH3 since I doubt you can buy a license that allows that.