"The Mullvad Browser is a privacy-focused web browser developed in a collaboration between Mullvad VPN and the Tor Project. It’s designed to minimize tracking and fingerprinting. You could say it’s a Tor Browser to use without the Tor Network."
We did not, we made a front end to the Google Search API.
Our search engine performs the searches on behalf of our users. This means that rather than using Google Search directly, our Leta server makes the requests.
https://github.com/mullvad/mullvad-browser
So basically like... hardened Firefox?