Mercury AVX2129.0.2

Firefox fork with compiler optimizations and patches from Librewolf, Waterfox, and GNU IceCat.

WindowsSystem ToolsOpen source

v129.0.2

62.8 MBscanned clean

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About

Mercury AVX2 lets Windows users browse the web with an x64 Firefox-based browser build that incorporates compiler optimizations tailored to its own code. It retains Firefox’s foundation while applying patches drawn from LibreWolf, Waterfox, GNU IceCat, Ghostery, and BetterFox. The result is aimed at people who want a customized Firefox experience for everyday browsing, testing, and development work.

The current 129.0.2 release adds compiler flags from Zen Browser and includes Mercury AVX2-related commits contributed back to Zen through a pull request. It disables Normandy, the component that permits Mozilla to change extension configurations remotely. JS_SHELL is enabled for developers using extensions such as Scratchpad to regain functionality removed from Firefox. Firefox View’s tab-strip functionality is enabled without enabling Firefox View itself; users can manually turn it on through about:config and add it to the tab strip with the buttons editor.

Alex313031 publishes Mercury AVX2 as open-source software for Windows, with x64 builds and builds for all operating systems. The macOS builds lack PGO because they are cross-compiled, which may reduce performance, and cross-compiling for macOS is currently broken after Apple objected to redistribution of Mozilla’s Xcode SDK. Developers building the project themselves can refer to its BUILDING.md and DEBUGGING.md documentation.

Architecture: x64

What's new in v129.0.2

- Finally updated it, plz don't hate me I know ya'll been waiting - Builds for ALL DA OSES! - Incorporated some compiler flags from Zen browser, AND, made some commits to Zen as well to add some of Mercury's AVX2 stuff. See > zen-browser/desktop#1216 Thanks to the author for talking to me on Reddit and then accepting my pull request. - Disabled "Normandy", a component that allows Mozilla to alter extension configurations at will remotely. (bleh wtf is that) - Enabled JS_SHELL, for devs looking to use extensions like https://addons.mozilla.org/en-US/firefox/addon/scratchpad/ to get a semblance of that functionality that they removed. - Tabstrip functionality of Firefox View is enabled, without actually enabling firefox view due to it's other bad stuff we don't want (You can still manually enable it in about:config, then re-add it to the tabstrip with the buttons editor). - MacOS builds lack PGO, since I had to cross-compile them. May reduce performance. NOTE: For those looking to build for themselves, cross compiling for MacOS is now broken since Apple complained about Mozilla redistributing the XCode SDK (of course 🙄). The workaround involves a lengthy process to package up the SDK from a Mac, then copy it to your Linux machine. It's outside the scope of these release notes, but I may add instructions to the //docs folder at a later date. UI Update: Next release will have some UI patches from Floorp, a popular Firefox fork. However, remember that Mercury doesn't attempt to heavily modify the UI from upstream Firefox, so don't expect Mercury to end up being a compiler optimized Floorp. I promise there won't be a freakin months long delay in updating. But I also tend to put Thorium and Codium first over my other projects. One man can only do so much, even with as often as I am on the computer doing nerd stuff.

Details

PlatformWindows
CategorySystem Tools
LicenseOpen source
PricingFree
Package IDAlex313031.Mercury.AVX2
Latest versionv129.0.2
File typeEXE
Architecturex64
File size62.8 MB
Published9/25/2026

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