I'm not terribly familiar with how to install fonts on mac, windows, and linux, and that especially goes for seeing these fonts in this repo (given that the source files are there). Not clear exactly which files I need for installation only, and where I put them, etc. Would be helpful to have an INSTALL.md file in the root, along side README.me, which explains the basic steps for the major OS's. Same goes for the "Source Sans" repo.
Isn't the font binary file in the download section?
The repo has just been updated with building instructions, and a shell script for building all the fonts from source.
Please have a look at the README.md file.