If you want to see the each step of read or write a qr code, can set #:express? to true.
Default will create folder .read.express for qr-read or .write.express for qr-write.
You can use #:express_path to specify another folder name.
Warning: express will generate a set of scribble files, it’s very slow, debug usage only.
scribble --htmls report.scrbl