A super extension that adds a lot of niceties and exposes many of GitHub’s hidden features. A must-have for serious development work. It’s always been well-maintained and kept up-to-date with GitHub’s continual UI changes.

Sublime addon

I don't sync my extensions, as I use different ones for different profiles, but on nearly every profile, this is without a doubt one of the very first extensions I install on a fresh installation. It's also THE best developer add-on available for Firefox, and I strongly recommend anyone who uses GitHub regularly to install it. Feature-rich, stable, updated all the time...what's not to love?

Very useful enhancements to the Github website that make life easier.

Excellent features, but so many that it might be better as several addons.