Yes, mix.exs files are arbitrary Elixir Code. mix.lock always has the same format, but still is elixir code.
Depending on the SCM (Git / Path, Hex, …), there will be an entry in the lockfile (optional) and it contains different content per SCM. For example, Hex saves the transitive dependencies, Git does not.
To get all the info out, I had to have mix running. (Mix.in_project)
