This is a UK coding layout for the Iris rev4 keyboard (created with the QMK configurator).
On Mac, you'll want to set your input language to British (not PC), and set your keyboard as ISO.
Reset your board, then:
git clone https://github.com/liamg/iris-layout.git
cd iris-layout
make flash
You'll probably need to do the above as root if you have issues.