It's a chrome extension for toggling javascript off/on for whatever domain you're currently on.
The extension I was using got hijacked and infected with malware so I made my own to replace it. Some backstory here: https://www.reddit.com/r/chrome_extensions/comments/1bqdfj6/disable_javascript_extension_has_malware/
It twiddles the javascript settings native to the browser.
These are the same settings you can inspect and change manually by going here:
chrome://settings/content/javascript
These settings apply on a domain basis, not on individual paths/pages under a domain. That was good enough control for me and kept the code for the extension to a minimum.
So if you turn off javascript when you're on analytics.google.com it only applies there and not at google.com. If you turn it off at example.com/pages/1 then it will be off at example.com/pages/2 and just example.com as well.
Javascript is enabled to start and you can click on the extension icon to disable it after the first time you visit. This extension doesn't have a setting to disable javascript by default and click to allow. Check out NoScript if you're looking for something like that.