Exporting to M4R Using Chain

‘.m4r’ is the file extension name for an iTunes ringtone. It’s exactly the same as ‘.m4a’ (= ‘mpeg4’ audio file), but with the ‘a’ changed to ‘r’ to differentiate their purposes.

Audacity’s useful ‘Chain’ function offers the following six export formats:
audacity_chain_export_formats.gif
However, Audacity’s File>Export Audio function seems to offer twelve or more export formats:
export_audio_formats.gif
How can I add ‘Export to M4A’ to Audacity’s Chain function? :frowning: