Privacy
The short version: Jahiz has nothing to hand over, because it never receives your file.
What is stored
Nothing, and right now there is nothing to store. Every conversion Jahiz offers today runs entirely in your browser: the file is read, converted and saved on your device, and no request carrying it leaves the page. There is no database, so there is no record of your file, its name, or the fact that you visited. Video and office documents will need a server when they land. That path streams the file to a temporary directory, converts it, sends it back, and deletes it as it finishes sending, and a sweeper removes anything older than 15 minutes whether or not a download happened.
Accounts
There are none. Jahiz asks for no email, sets no login, and has nowhere to attach a history even if it wanted one.
Third parties
Your file is not sent anywhere. It is converted on your device, so no other service receives it, and no advertising or analytics script runs on the page you convert from.
Logs
The page itself is served over the network, so a request for it reaches a server like any web page. Nothing about your file is in that request, because your file is never in one. When the server tier lands it will count requests to keep a single visitor from consuming every conversion slot, holding an address and a timestamp that expire on their own and are never tied to a file.