Read, as a QR code (4)
I believe the answer is:
scan
'read as a qr code' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for scan that I've seen before include "Skim; examine" , "convert metres into feet?" , "Look over cursorily" , "Examine, view" , "Examine (to transmit)" .)