Its that same type of Question which AMMs can't answer & the ones that can are the Manufacturers or people that know about the development stages of the Aircraft type.
On the P8 panel of a B757,any version,not sure how its on the B767s.
The Fire test panel on P8 has a test button for "ENG" & "ENG/APU/CARGO"
Why is the ENG test button duplicated.Was there a reason for Boeing to do that.As both Tests test the ENG Fire/Overheat Elements.
Or was it to isolate a Fault.