Where can I learn more about Lemmy's Security Model and its Privacy Policy?

Title.

I have started to use Lemmy quite frequently in the last few days. I really like it, but I haven't been able to find any documentation that explains how my data is being handled, what kind of data is being collected and how it is being used and neither have I been able to find an in-depth explanation – or any explanation for that matter – about Lemmy's security model.

Would anyone please provide a source where I could find that info?