Mullvad Browser 14.0, built on Firefox ESR 128, reintroduces Firefox Screenshots and Picture-in-Picture, with privacy enhancements. Security levels have also been removed from the toolbar, as altering the security level can modify the browser fingerprint.
https://alternativeto.net/news/2024/11/mullvad-browser-14-0-brings-firefox-screenshots-and-pip-back-and-improves-privacy-and-security/