Download Opus UI DevTools

Name: Opus UI DevTools
Author: Big Bad Waffle

By: Big Bad Waffle

Download Opus UI DevTools (current and past versions) for Firefox

Latest Version: 1.2.3 Updated: 2 months ago

Ready to install?

Opus UI DevTools is available to install from Firefox Add-ons Store and for download from this page.

View source code

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Total downloads

Available versions

You can find the current and older versions of Opus UI DevTools 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	Timestamp
1.2.3	XPI · ZIP · Source code	35.93KB	2026-05-12
1.2.2	XPI · ZIP · Source code	35.69KB	2025-06-23
1.1.0	XPI · ZIP · Source code	33.63KB	2025-04-09
1.0.1	Paid users only	23.07KB	2025-04-06

2026-05-12 · 0 downloads

XPI ZIP Source code

2025-06-23 · 0 downloads

XPI ZIP Source code

2025-04-09 · 0 downloads

XPI ZIP Source code

2025-04-06 · 0 downloads

Paid users only

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 Opus UI DevTools ZIP file.
In Firefox browser, go to about:addons to open Add-ons Manager
Click on ⚙, Install Add-on From File
Select the Opus UI DevTools ZIP file from step 1. Opus UI DevTools is now installed on your browser.