By: Weary Galaxy Add-on
Download Simple CSS Injector (current and past versions) for Firefox
Latest Version:
1.0.0 Updated:
9 months ago
Ready to install?
Simple CSS Injector is available to install from Firefox Add-ons Store and for download from this page.
Available versions
You can find the current and older versions of Simple CSS Injector here. You can download the archived versions or inspect their source codes.
As a free user, you can download up to 3 latest versions.
Upgrade to download older versions
| Version | Download | Size | Download count | Timestamp |
|---|---|---|---|---|
| 1.0.0 | XPI · ZIP · Source code | 832.56KB | 0 | 2025-11-12 |
1.0.0 832.56KB
Install XPI file
An XPI file, short for "XPInstall," is a compressed file format used primarily by Mozilla applications, like Firefox and Thunderbird, to distribute and install add-ons or extensions. These files are similar in function to CRX files for Chrome but cater to the Mozilla ecosystem.
- Simply drag-and-drop the XPI into Firefox to install the add-on.
Install ZIP file
- Download the Simple CSS Injector ZIP file.
- In Firefox browser, go to
about:addonsto open Add-ons Manager - Click on ⚙, Install Add-on From File

- Select the Simple CSS Injector ZIP file from step 1. Simple CSS Injector is now installed on your browser.
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