The ultimate theme manager for Firefox-based browsers.
JavaScript
1,508
1,327 commits
updated Oct 16, 2026
Sine is a community-driven mod/theme manager for all Firefox-based browsers, designed to be a more efficient, powerful, user-friendly, and compatible alternative to manual installation.
[!NOTE] A manual installation guide is available in the documentation page for installation.
The automatic installer is the easiest way to set up both Sine and its bootloader with minimal effort. Starting with version 2.0, installers are available for:
x64 and ARM architecture CPUs are also supported.
xattr -d com.apple.quarantine ./sine-osx-arm64
chmod +x ./sine-osx-arm64
sudo codesign --force --deep --sign - sine-osx-arm64
./sine-osx-arm64
That’s it! Sine should now be installed and ready to use.
Sine boasts a powerful suite of easy-to-use tools for everyone, technical, or non-technical. Let's look through some of these features:
Sine has a marketplace that is built-in to the settings gui for easy access. This marketplace is where the user adds and views Sine-compatible mods.
Am I limited to this settings gui?: Absolutely not. Sine provides support for installing mods from our website too.
Every time a pull request gets published to a repository, it seems like it just adds to the stack of never-ending overflow. Sine makes this process simple. All you have to do is make an issue with a template. Assuming your project is already Sine-compatible, it'll work just fine. Plus, the developers of Sine are active enough to handle your pull requests quickly.
What about updating?: Sine does not require update requests and pulls them straight from your repository. This means that you will never have to worry about github issues being outdated or have to tell your user to update to the latest version.
Sine makes the process of adding unpublished mods easy as long as they have a valid mod format. You simply type in the name of the repository (folder if needed) and Sine handles the rest.
Built-in settings: Sine has built-in settings that allow you to control what you like and don't like about it, and if you ever don't feel like you have enough control, you can create an issue or discussion here and we'll handle it right away.
Mod management: Sine gives the power to turn on or off updating for certain mods, as well as auto-updating on browser start, giving the control you need.
Mod preferences: Along with a powerful suite of tools to customize your browser experience, Sine comes with extra preference features for mods. Fortunately for you, Sine has so many, we have listed them in a wiki here.
Sine is designed to be highly compatible and as such, it offers support for userChrome, userContent, the Zen mod format (chrome), and mods missing typically necessary metadata.
| Free code signing on Windows provided by SignPath.io, certificate by SignPath Foundation |
Built with ❤️ by CosmoCreeper and some amazing supporters!
Licensed under Mozilla Public License v2.0.
30 followers · starred Jul 2025
38 followers · starred Dec 2025
116 followers · starred Jun 2025
14 followers · starred May 2026
The ultimate theme manager for Firefox-based browsers.
JavaScript
1,508
1,327 commits
updated Oct 16, 2026
Sine is a community-driven mod/theme manager for all Firefox-based browsers, designed to be a more efficient, powerful, user-friendly, and compatible alternative to manual installation.
[!NOTE] A manual installation guide is available in the documentation page for installation.
The automatic installer is the easiest way to set up both Sine and its bootloader with minimal effort. Starting with version 2.0, installers are available for:
x64 and ARM architecture CPUs are also supported.
xattr -d com.apple.quarantine ./sine-osx-arm64
chmod +x ./sine-osx-arm64
sudo codesign --force --deep --sign - sine-osx-arm64
./sine-osx-arm64
That’s it! Sine should now be installed and ready to use.
Sine boasts a powerful suite of easy-to-use tools for everyone, technical, or non-technical. Let's look through some of these features:
Sine has a marketplace that is built-in to the settings gui for easy access. This marketplace is where the user adds and views Sine-compatible mods.
Am I limited to this settings gui?: Absolutely not. Sine provides support for installing mods from our website too.
Every time a pull request gets published to a repository, it seems like it just adds to the stack of never-ending overflow. Sine makes this process simple. All you have to do is make an issue with a template. Assuming your project is already Sine-compatible, it'll work just fine. Plus, the developers of Sine are active enough to handle your pull requests quickly.
What about updating?: Sine does not require update requests and pulls them straight from your repository. This means that you will never have to worry about github issues being outdated or have to tell your user to update to the latest version.
Sine makes the process of adding unpublished mods easy as long as they have a valid mod format. You simply type in the name of the repository (folder if needed) and Sine handles the rest.
Built-in settings: Sine has built-in settings that allow you to control what you like and don't like about it, and if you ever don't feel like you have enough control, you can create an issue or discussion here and we'll handle it right away.
Mod management: Sine gives the power to turn on or off updating for certain mods, as well as auto-updating on browser start, giving the control you need.
Mod preferences: Along with a powerful suite of tools to customize your browser experience, Sine comes with extra preference features for mods. Fortunately for you, Sine has so many, we have listed them in a wiki here.
Sine is designed to be highly compatible and as such, it offers support for userChrome, userContent, the Zen mod format (chrome), and mods missing typically necessary metadata.
|
| Free code signing on Windows provided by SignPath.io, certificate by SignPath Foundation |
Built with ❤️ by CosmoCreeper and some amazing supporters!
Licensed under Mozilla Public License v2.0.
30 followers · starred Jul 2025
38 followers · starred Dec 2025
116 followers · starred Jun 2025
14 followers · starred May 2026