RemixIconEx.Editor.heading

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

heading(icon_css_class \\ "icon")

iex> Elixir.RemixIconEx.Editor.heading()
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" class="icon">
  <path d="M17 11V4h2v17h-2v-8H7v8H5V4h2v7z" />
</svg>

example usage

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