\usemodule[fnt-20,art-01]

\starttext

\definefontfeature
  [freeserif-default]
  [default]
  [script=latn]

\setvariables
  [otftracker]
  [font=file:freeserif.ttf,
   size=24pt,
   figure=,
   features=freeserif-default,
   title=Feature Check,
   sample={dadedidodufafefifofufrflftlale}]

\setvariables
  [otftracker]
  [font=file:freeserif.ttf,
   size=24pt,
   figure=,
   features=freeserif-default,
   title=Feature Check,
   sample={lilolutatetitotu}]

\stoptext