Thank you!

Should groups of checkboxes like this have a label? In this case it could be "Visible To". It might be obvious enough already though.

We could add such a heading, but in that case it should be added to other Ray Visibility panels too.

@Adrian Newton (TFS) do you feel like adding these headings? Otherwise I can add them too and commit this, but I won't just hijack your contribution ;)

Sorry for delay, for some reason I didn't get the update.

Happy to add, but looking at the tooltips 'Visible for' might be better.

Also, given the space, should we change

Diffuse -> Diffuse Reflection &
Glossy -> Glossy Reflection

Also, if the changes to Diffuse & Glossy are ok, is the acceptable way to change the text within RNA settings or text additions to the col.prop()?

Personally I see no need for the heading.

In D7612#187255, @Adrian Newton (TFS) wrote:

Also, given the space, should we change

Diffuse -> Diffuse Reflection &
Glossy -> Glossy Reflection

No.