title: How to validate pip's --extra-index-url?
body: <p>I am unable to find certain packages that should be found from a local package index that I've defined with the <code>--extra-index-url</code> in my global <code>pip.ini</code> file.</p>
  
  <p>How can I validate that my <code>pip</code> is using this properly? In my scenario I'm using a virtual environment.</p>
  
  <p>I have tried <code>pip config list</code> because it sounded promising in <code>pip help</code>, but I get <em>nothing</em> as an output.</p>