A lot of times depends on the team setup and the expertise level of the team itself. I dont see a reason to say that it should differ that much from your usual stream aligned teams - PM is for identifying the problems that need to be solved and the team is for the How. Or PM is to show the direction, and EM is to make sure the ship gets there. The details there would be team specific, as long as you dont go against "organic" rules, a'la create something that works on paper but in real life wont be followed because it does not make sense.
Havent seen a version where PM would act as Tech Lead and this actually being a good idea.