They address this directly under the section entitled "Open-Source, not Open-Contribution":
SQLite is open-source, meaning that you can make as many copies of it as you want and do whatever you want with those copies, without limitation. But SQLite is not open-contribution. In order to keep SQLite in the public domain and ensure that the code does not become contaminated with proprietary or licensed content, the project does not accept patches from unknown persons.
In other words, the reasoning is that since the code is released to the public domain, they want to ensure they can continue doing so without encumbering or confusing future releases with tainted contributions. Quite admirable.
It's pretty normal for open source projects to refuse contributions from anyone who hasn't signed a CLA or something similar. The alternative is a legal nightmare.
Just to be clear: We do not have any support contracts with the
US military, nor any other US government agency, nor any other
government entity, either inside or outside the US. Not that
we would turn down such work if it were available, it is just
that is has never come up.
Until I read the transcript, just now, I had confused SQLite's origins (a General Dynamics contract with the US Navy) with its through-2050 support contract, which, it turns out, is with Airbus.
There are 3 people on the planet who can make changes to it and one person who can work on their custom made source control system. Single points of failure are not sustainable.
Well, it's been popular for 20 years, so that sounds fairly sustainable to me. A lot of projects with many more contributors have come and gone in that time period.
Either way, that doesn't make it "closed source" like you said in the other comment.
> There are 3 people on the planet who can make changes to it
Anyone on the planet can make changes to it and distribute those changes. The only thing those 3 can do that the rest of us cannot is get their changes into the copies distributed at sqlite.org.
SQLite is open-source, meaning that you can make as many copies of it as you want and do whatever you want with those copies, without limitation. But SQLite is not open-contribution. In order to keep SQLite in the public domain and ensure that the code does not become contaminated with proprietary or licensed content, the project does not accept patches from unknown persons.
In other words, the reasoning is that since the code is released to the public domain, they want to ensure they can continue doing so without encumbering or confusing future releases with tainted contributions. Quite admirable.