The fonts' source files and build instructions are available in the [repository's `master` branch](https://github.com/adobe-fonts/source-sans/tree/master).
[Open an issue](https://github.com/adobe-fonts/source-sans/issues) or send a suggestion to Source Sans' designer [Paul D. Hunt](mailto:opensourcefonts@adobe.com?subject=[GitHub]%20Source%20Sans%20Pro), for consideration.