OK guarantee was too strong of a word, I meant more like “assurance” or “elements to believe”.

Either way, my point stand: you did not audit the code you are running, even if open source (let’s be honest). I am a selfhoster myself and I don’t do either.

You are simply trusting the software author and contributors not to screw you up, and in general, you are right. And that’s because people are assholes for a gain, usually, and because there is a chance that someone else might found out the bad code in the project (far from a guarantee). That’s why I quoted both the policy and the business model for kagi not to screw me over. Not only it would be illegal, but would also be completely devastating for their business if they were to be caught.

But yeah, generally hosting yourself, looking at the code, building controls around the code (like namespaces, network policies, DNS filtering) is a stronger guarantee that no funny business is going on compared to a legal compliance and I agree. That said, despite being a selfhoster myself, I do have a problem with the open source ecosystem and the inherent dependency on free labour, so I understand the idea of proprietary code. Ultimately this is what allowed kagi to build features that make kagi much more powerful than searXNG for example.