RemixIconEx.System.function

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

function(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.System.function()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M3 3h8v8H3V3zm0 10h8v8H3v-8zM13 3h8v8h-8V3zm0 10h8v8h-8v-8zm2-8v4h4V5h-4zm0 10v4h4v-4h-4zM5 5v4h4V5H5zm0 10v4h4v-4H5z" />
</svg>

example usage

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