Thank you for the detailed response. May I ask one more question: In my current game as Prussia in the modern age, I want to place specialists with the goal to maximize production. If a specialist maybe gives me only 2 production (like in the image you posted above), this will only appear in that specialist panel. So I have to hover the mouse over each tile to see if I get a production bonus, correct?
I have a tile which has only an altar from antiquity age and no special features or adjacencies. In the city screen there are no yields shown, but the specialist panel says that I get +10 yields, including the +2 production. (sorry if that sounds confusing, English is not my native language)
So do I get those +10 or is that a misunderstanding on my part?