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Licensing of Software on Github:
A Quantitative Analysis

Aaron Williamson

Senior Staff Counsel

Software Freedom Law Center

Why does it matter?

Guides our response

How can we test this?

Follow the kids to Github



Preliminary clean-up


Not all the Githubs, really

Languages used on Github

Guaranteed to overlook licenses...

FOSSology results over-inclusive


...out of 1,692,135 repositories (14.9%) have a top-level license file


...only announce the license in the README file


...most licenses found in one repo (gdb, binutils, newlib)

What is gitPAN?

gitPAN is a project to import the entire history of CPAN (known as BackPAN) into a set of git repositories, one per distribution.

What is CPAN?

CPAN is the Comprehensive Perl Archive Network at It is an archive of tens of thousands of Perl modules written by thousands of authors. A good interface to it is

Interpreting the data

Explanations for the change

Licensing communities

Coalesce around popular infrastructure and personalities

Languages used on Github

Rails licensing philosophy

jQuery licensing history

10 random(ish) jQuery plugins on Github

Go home, jQuery, you're drunk

Why does the jQuery community have these issues?

Ruby license variants

Flight from GPL?


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