This extension won't work anymore according to GitHub's Blog: Git.io no longer accepts new URLs.
A cross-browser extension for GitHub's URL shortener (git.io).
https://github.com/*https://*.github.com/*https://*.github.iohttps://*.github.io/*https://*.githubusercontent.com/*
On Chrome/Chromium-based browsers, you can:
- Enable
Developer mode. (How?) - Clone the repository:
git clone https://github.com/mahdyar/git.io-extension.git
- Go to
chrome://extensions/and click onLoad unpackedand load the folder from previous step.

