It’s an experimental way to calculate how “volatile” is a project
source code repository, by comparing the amount of dead code (rarely touched)
with the amount of actively modified one. More or less detailed theoretical summary
is in theory.pdf.

You need to have Ruby 2.6+ installed. Then you install this tool:

$ gem install volatility

Then, you run it:

$ volatility --help

How to contribute

Read these guidelines.
Make sure your build is green before you contribute
your pull request. You will need to have Ruby 2.3+ and
Bundler installed. Then:

$ bundle update
$ bundle exec rake

If it’s clean and you don’t see any error messages, submit your pull request.