RemixIconEx.System.side_bar

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

side_bar(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.System.side_bar()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M3 3h18a1 1 0 0 1 1 1v16a1 1 0 0 1-1 1H3a1 1 0 0 1-1-1V4a1 1 0 0 1 1-1zm5 2H4v14h4V5zm2 0v14h10V5H10z" />
</svg>

example usage

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