Al, that link for the Eaton AFCI device is just a Spec Link. I couldn't find a link to their installation instructions. But, the Eaton device that I picked up at my local supply house has instructions that say the same as the Leviton AFCI instructions with the same location picture. I suspect that the instructions will be similar for all devices because it may be part of the listing. Notice the AFCI device must also be installed in a box with only two 2-wire cables.
So, according to the instructions if I was adding the AFCI device to a branch circuit with a homerun to a lighting outlet...I would have to intercept the branch circuit before the lighting outlet to add the device. Or put it next to the main panel.