A QR Code is a unique machine-scannable image.
Basically, a QR code works in the same way as a barcode at the supermarket.
The QR code on your G2G pass can be scanned by a Police Officer to quickly verify your pass details and help you get on your way sooner.
Here is an interesting Wikipedia article on QR codes: https://en.wikipedia.org/wiki/QR_code
Example QR Code:
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