> For legal reasons, we could not contribute directly, but we could discuss the required changes with someone from the SQLite team and then iterate with them by testing or commenting.

Ah, here's the catch! I knew SQLite didn't accept code contributions, I was suprised they managed to contribute anyway, and then this sentence clarified the situation. So they indeed did not manage to contribute their code itself, but the SQLite team agreed to write this code themselves. I wonder what was the SQLite team's motivation behind this cooperative work.

To summarize, instead of using one of the OSS licenses, the copyright holders simply declare the source to be in the public domain. In order to preserve that status they don't accept patches unless you submit some signed document that you agree with that.

To make things more complicated, they also use their a relatively niche version management system instead of git. Which would complicate making contributions (if they accepted them).

There's a popular fork that fixes all of these issues: https://github.com/libsql/libsql It is MIT licensed, on Github, and open for contributions.

Kind of a weird legal situation for a popular project like this that so many people depend on to have. Not judging; but it is odd. Seems like a lot of wasted efforts between users, would be contributors, and the people that forked this thing to address all that.