I’m labeling all my PCBs with QR code, pointing to a url where I host all documents of the project (usually generic to my domain and then a redirection, s.t. if e.g. git changes url scheme, it still works).
This is something that can be done with existing tools:
Use the QR code genreator in inkscape with a custom path set to l 0,-.99 l .99,0 l 0,.99. You might want to select the “invert” checkbox if the QR code is put in white silkscreen. Then export the drawing as a DXF.
In Horizon EDA, import the DXF, select the boxes from the QR code and use the “line loop to polygon” tool to convert them into filled polygons. For scaling the QR code, use the “scale” tool. If the QR code is inverted, surround it with polygons so that it can be read properly: