# fontspec: what does Renderer=Basic do?

I'm writing a document using LuaLaTeX on Windows, using Arial (please do not comment on that) as its main font with:

\usepackage{fontspec}
\defaultfontfeatures{Ligatures=TeX}
\setmainfont[Renderer=Basic]{Arial}

To keep the usual TeX substitutions I used Ligatures=TeX, but this does not work unless using Renderer=Basic additionally.

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