While the developer may be well-intentioned, there's still a great amount of risk you are taking in using this or any other extension, because they can be easily updated to a new version without you ever being notified about it.
Learned my lesson after having to deal with a Bitcoin Ticker that was automatically replacing the withdrawal addresses in various exchanges to the ones pointed out in the extension. I was on the verge of losing everything.
If you want to use it, at least install this:
Extensions Update Notifierhttps://chrome.google.com/webstore/detail/extensions-update-notifie/nlldbplhbaopldicmcoogopmkonpebjm?hl=enor
Install the Chrome extension source viewer from the Chrome webstorehttps://chrome.google.com/webstore/detail/chrome-extension-source-v/jifpbeccnghkjeaalbbjmodiffmgedin/related1 - Download a specific version of a Chrome extension.
2 - Go to your extensions folder in Chrome, turn on Developer Mode, and click on the options link below Chrome extension source viewer
3 - Open the viewer
4 - Open the recently downloaded "insertname" file
5 - Click "Download" in the upper left corner. Finder will open showing you a null folder that contains the "insertname" logo, a javascript file, and the manifest.
6 - Open the Manifest JSON file (Any text editor will do)
7 - Change the update url (found in quotations) to
http://127.0.0.1 (you own local machine IP) and save the file
8 - Optional: Go to the Chrome Developer tools and choose to pack a chrome extension to create a .crx file again.
9 - Drag the entire null folder or the .crx file (with the newly edited manifest file) into your Chrome Extensions page with developer mode turned on.