RemixIconEx.Document.folder

You're seeing just the function folder, go back to RemixIconEx.Document module for more information.
Link to this function

folder(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.Document.folder()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M4 5v14h16V7h-8.414l-2-2H4zm8.414 0H21a1 1 0 0 1 1 1v14a1 1 0 0 1-1 1H3a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1h7.414l2 2z" />
</svg>

example usage

svg.icon {
  width: 96;
  height: 96;
}