title: How to install Firefox Developer edition via Homebrew?
body: <p>This is how to install Firefox via Homebrew:</p>
  <pre><code>brew install --cask firefox
  </code></pre>
  <p>But how to install the 'Firefox Developer edition'?</p>
  <p>Everything I tried fails with 'Error: Cask '...' is unavailable: No Cask with this name exists.'</p>
  <pre><code>brew install --cask firefox-developer-edition
  brew install --cask firefox-nightly
  </code></pre>
  <p>What's the correct command?</p>