Geckium is a Mozilla Firefox (115 - latest) CSS and JS modification that restores the look and feel of past Chromium (or Google Chrome) releases, spanning from 1.0 to 58, while also bringing Chromium Theme support to Firefox, bringing obscure prerelease content to the limelight and retrofitting new content into every design.
Just install Geckium normally by deleting your chrome
folder and placing Geckium's chrome
folder in its place - upon launching Geckium it will automatically migrate the settings you had from Silverfox to Geckium's settings.
Geckium is designed for the following platforms:
- Linux (tested on Arch, by the way, Fedora KDE, Fedora, Kubuntu and Feren OS)
- Windows 7
- Windows 8.1
- Windows 10 (with Native Controls Patch)
- Windows 11
- macOS* (tested on Sonoma and Sequoia)
*Mac OS X's 3-6 eras may be inaccurate as we were unsuccessful in finding DMGs of those versions
However,
- Compatibility with Firefox forks is never guaranteed - minor adjustments will be made by Geckium to accommodate itself in Firefox forks, but issues not seen in Firefox may still occur.
- Due to the nature of how their packages are created, Geckium CANNOT be used in Mozilla Firefox from Flathub nor Ubuntu (and Snap Store). Ubuntu users will have to install Firefox from the Mozilla PPA in order to use Geckium.
To begin, download Geckium from the Releases page.
ℹ Once running for the first time, Geckium will restart Firefox automatically 1-2 times while it sets up required settings, migrations, and so on - if Firefox doesn't re-appear after restarting itself, terminate Firefox and launch it again (that is an upstream bug with Firefox).
To improve your Geckium experience, you should also install Tampermonkey and, using Tampermonkey, install the official Geckium UserScript for enhanced functionality.
- Open Firefox, and in the address bar go to
about:support
- Look for
Profile Folder
and next to it pressOpen Profile Directory
- Copy the
chrome
folder (and, if it's your first time installing Geckium,chrThemes
folder) from theProfile Folder
folder in your copy of Geckium to the resulting file manager's window's currently displayed folder - Navigate to
File System/usr/lib/firefox
(orFile System/usr/lib/firefox-esr
if using Mozilla Firefox ESR) - Copy the contents of the
Firefox Folder
folder in your copy of Geckium to thefirefox
/firefox-esr
folder (if your file manager does not ask for Superuser privilleges automatically, you will need to manually open your File Manager with Superuser privilleges) - Back in the Firefox window, scroll to the top, and press
Clear startup cache
followed by confirming the confirmation that then displays - You are now running Geckium, and will see a setup window appear to start setting up Geckium - enjoy!
- Open Firefox, and in the address bar go to
about:support
- Look for
Profile Folder
and next to it pressOpen Profile Directory
- Copy the
chrome
folder (and, if it's your first time installing Geckium,chrThemes
folder) from theProfile Folder
folder in your copy of Geckium to the resulting File Explorer window's folder - Find a Mozilla Firefox shortcut, right-click it and select
Open file location
- Copy the contents of the
Firefox Folder
folder in your copy of Geckium to the resulting folder (depending on how you installed Firefox, you may need to have administrator privilleges to perform this step) - Back in the Firefox window, scroll to the top, and press
Clear startup cache
followed by confirming the confirmation that then displays - You are now running Geckium, and will see a setup window appear to start setting up Geckium - enjoy!
⚠ FOLLOW THE STEPS CAREFULLY - FAILURE TO PERFORM THESE STEPS PROPERLY WILL BRICK YOUR CURRENT COPY OF MOZILLA FIREFOX FOR MACOS
- Open Firefox, and in the address bar go to
about:support
- Look for
Profile Folder
and next to it pressOpen in Finder
- Copy the
chrome
folder (and, if it's your first time installing Geckium,chrThemes
folder) from theProfile Folder
folder in your copy of Geckium to the resulting File Explorer window's folder - DO NOT QUIT FIREFOX - find your copy of Mozilla Firefox, right-click it and select
Open Package Contents
- Go to Contents -> Resources, and then copy the contents of the
Firefox Folder
folder in your copy of Geckium to this folder (you will need to merge folders if prompted to) - Back in the Firefox window, scroll to the top, and press
Clear startup cache
followed by confirming the confirmation that then displays - You are now running Geckium, and will see a setup window appear to start setting up Geckium - enjoy!
Credits can be found within Geckium Settings's About page upon opening Geckium.
Geckium is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License license, excluding the parts of Geckium that are forked off Firefox or Chromium - for these files, their licenses can be found in the files their code resides in.
For more information about Geckium's Creative Commons license, see LICENSE.md or click the license below.