Waterfox

MPL-2.0, 6,311 stars as of September 2026, currently at 6.7.4 (released September 22).

Waterfox dates back to 2011, first as a 64-bit build of Firefox and later as an independent fork. At the end of 2019 it was acquired by the advertising company System1; in 2023 founder Alex Kontos bought it back to run independently, and it now belongs to BrowserWorks Ltd, which Kontos wholly owns.

Like LibreWolf, it removes the parts of Firefox that report back to the vendor. The trade-offs differ:

• It follows Firefox ESR (Extended Support Release), so the interface changes more slowly than regular Firefox. That suits people who do not want to relearn the UI every month.
• Telemetry is disabled and locked at build time, and the privacy policy is specific: no sponsored top sites, no sponsored new tab stories, no Pocket.
• It adds interface features Firefox lacks: tree tabs (pages nest under the page that opened them), a bottom status bar, and private tabs inside a normal window.
• The desktop version has a built-in ad blocker, on by default since May 2026. DNS lookups can go through an Oblivious HTTP relay, separating who you are from what you asked.
• It updates itself, unlike LibreWolf, which relies on package managers or manual downloads. The Android version is on Google Play.

To be clear about:

• It earns money from search ad revenue. The default search engine is Qwant in 26 regions, including the US, the UK and most of Europe, and DuckDuckGo elsewhere, with Waterfox attribution parameters added to searches. The built-in ad blocker allows ads on the default search engine's result pages while blocking ads everywhere else. The project says you can change the search engine or block partner search ads at any time. That is why it does not carry the "No Ads" badge here.
• The default search engine changed several times this year. Startpage was removed in May 2026 in favour of 1.org as a stopgap, then replaced by Qwant and DuckDuckGo in July. When the revenue source moves, the defaults can move with it.
• Network requests are not zero. The privacy policy lists connections that expose your IP: search suggestions, the DNS relay, an update check every 12 hours (with version and OS details but no browsing data), and filter list downloads.
• Fingerprinting resistance is weaker than LibreWolf or Mullvad Browser. Its aim is a clean Firefox, not maximum privacy.
• Being based on ESR means new web platform features arrive later, and a few very new sites may not behave exactly as they do in current Firefox.