title: What other special modules (files) exist at the package level?
body: <p>I know of only two filenames that will be interpreted meaningfully: <code>__init__.py</code> and <code>__main__.py</code></p>
  
  <p><code>__init__.py</code>: The init file for a package. Executed when a package is first imported/imported from. If this file is present, then the directory is considered a package (there also exists "namespace packages" that don't have init modules)</p>
  
  <p><code>__main__.py</code>: The main entry point for a package. This file is executed when running the package from the commandline. (ex: <code>python -m PackageName</code>)</p>
  
  <p>What other files can exist and what do they do?</p>