If you are a web developer, involved in security, or just trying to fix a server problem, then it can sometimes be effective to see exactly what's energizing a website.
Wappalyzer is a free to use browser extension for Chrome and Firefox which finds servers, content management systems, analytic tools, eCommerce platforms, advertising frameworks and more.
The extension adds numerous icons to your Firefox address bar, every one representing a popular web component (jQuery, PHP, etc). There's also an independent Wappalyzer icon, and clicking this shows the complete list, sometimes with their version numbers.
If you are thinking that means Wappalyzer must send its discovery results back to the developer, then you are right. This is done anonymously, though, so doesn't create any significant privacy risk, and if you are still unhappy then it's easy to turn off (click the icon, select Settings, clear "Anonymously send reports").
Pros
- Works on most websites.
- Useful for developers, marketers.
Download the free Wappalyzer for Chrome