Good catch, I'm glad that it's a best practice. I wasn't trying to shame those projects, I'm not a rubiest so I was just trying to figure out how someone might gain access to a secret token.
That's an interesting issue (Django has the same issue with its SECRET_KEY). If you have an open-source project that utilizes these kinds of technologies, you need to keep your secret key secret.
As it says in the Django settings:
"Make this unique, and don't share it with anybody."
Incidentally, this is one reason why the 12-factor app methodology stores configuration in environment variables, not source files. http://www.12factor.net/config
https://github.com/search?utf8=%E2%9C%93&q=secret_token....