ules can define a list of secrets that they want access to. These are all
      absolute paths (beginning with <code class="code">/</code> or
      <code class="code">~</code> and aren't copied to the build directory;
      instead they can be located using the environment variable
      <code class="code">$SECRETS</code>.<br />
      They're useful for things like signing or access keys that you don't want
      to check into version control but still might be necessary for building
      some rules.
    <