$ convert -density 600 README.md.qr.pdf tif:- | zbarimg --raw -q -Sdisable -Sqrcode.enable -
convert-im6.q16: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408.
convert-im6.q16: no images defined `tif:-' @ error/convert.c/ConvertImageCommand/3258.
ERROR: no decode delegate for this image format `' @ error/constitute.c/ReadImage/560