Can anyone tell me which view I have to edit to change the size of the generated QR-Code on the invoices?

I'd like to reduce the size of the code by adding

style="width: 75px;"

at the end of the qrcode's image tag. But I can't find the neccessary view block anywhere. At least not by checking the filtered view list which I assumed it might have been in.

The used version is 17.0-20240905 (Community Edition)

Thanks in advance!