View source code of Chrome extensions, Firefox addons or Opera extensions (crx/nex/xpi) from the Chrome web store and elsewhere.
How to Find & View the Files Installed by a Chrome Extension
Under New Management' Alerts You When a Chrome Extension Changes Owners
View Rendered Source Chrome Web Store (Plugin)
Chrome extension source viewer - 在线下载、查看Chrome 扩展源码[Chrome、Opera、Firefox 扩展]-反斗软件
Here's One Way to Check That Your Chrome Extensions Are Safe
How to view a webpage's source code in Google Chrome mobile version - Quora
Extension Source Viewer 1.6 for Firefox free download - Software reviews, downloads, news, free trials, freeware and full commercial software - Downloadcrew
Reverse Engineering an Extension – Jillian Zhong – Jillian's blog for NYU ITP projects
Quick source viewer
Chrome extension source viewer - 在线下载、查看Chrome 扩展源码[Chrome、Opera、Firefox 扩展]-反斗软件
Testing Chrome Extensions with Selenium - DEV Community