Composer package or module?

This question came up when I saw the myth/auth package. As it contains views I also wondered how I could change them and include those changes in my repository without messing up the original content. So I wondered if this type of package (and others) would be better delivered as a module, and when each case is recommended.
  Reading more, I found the answer: https://github.com/lonnieezell/myth-auth...g.md#views
Sorry for the early question.