title: How to list existing branches of a git submodule (without initializing it first)?
body: <p>I have a project with lots of submodules for some specific reason. I just want to know which branches exist for each submodule. I know that I could initialize each submodule with </p>
  
  <pre><code>git submodule update --init
  </code></pre>
  
  <p>and perform a </p>
  
  <pre><code>git ls-remote --heads {URL} 
  </code></pre>
  
  <p>on each submodule to get the currently existing branches of that submodule (git branch -r also lists already deleted branches). But since our project exists of many submodules the initialization above needs a lot of time on the first run. Is there a way to get the existing branches without initializing the submodules?</p>