RemixIconEx.System.upload

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

upload(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.System.upload()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M3 19h18v2H3v-2zM13 5.828V17h-2V5.828L4.929 11.9l-1.414-1.414L12 2l8.485 8.485-1.414 1.414L13 5.83z" />
</svg>

example usage

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