RemixIconEx.System.alert

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

alert(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.System.alert()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M12.866 3l9.526 16.5a1 1 0 0 1-.866 1.5H2.474a1 1 0 0 1-.866-1.5L11.134 3a1 1 0 0 1 1.732 0zm-8.66 16h15.588L12 5.5 4.206 19zM11 16h2v2h-2v-2zm0-7h2v5h-2V9z" />
</svg>

example usage

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