@dc42 It's no problem whatsoever, but I find it a little odd that both M20 S2 and S3 include the "Begin file list" and "End file list".
Begin file list
{"dir":"0:/gcodes/","first":0,"files":[{"type":"d","name":"Test","size":0,"date":"2022-03-14T00:48:18"},{"type":"f","name":"clock_contour.nc","size":5704,"date":"2022-03-10T19:47:08"}],"next":0}
End file list
I would expect a pure JSON response, like M36 and other commands that return JSON do. I can understand the header and footer for the text S0 response.