Then the mistake was made many years ago by releasing the code under GPLv2, with no obligation to contribute back.

Picturesque and poignant.

This is a specific kind of mass gaslighting and sunk cost fallacy: “Think of all the money we spent on cleaning, don’t you believe it’s clean?” /s

Buy a regular standalone USB webcam, and point it at the computer screen with the code in some corner.

No printing required.

Accept that you will require some workaround since you do not wish to install the QR app.