I will keep "Googling" around to learn more. But, I found this right away:
"Lastly, bread with no salt will also has a crust which is lighter in colour (given the same baking time and oven temperature). This can be explained as follows. Salt will slow down fermentation, so when there is no salt, the yeast activity will increase i.e. the yeast will metabolise more sugar in a given period of time. As a result there will be less sugars left in the dough and the pH of the dough will be lower (more acids will be formed). Sugars play (together with proteins, moisture and heat) an important role in the Maillard reaction. But the Maillard reaction is also influenced by the pH : a higher pH will speed up the Maillard reaction. So in this case where the pH is lower and where there are less sugars left, the colour of the crust is lighter."
So, acidic dough has a less strong Maillard reaction (browning, etc.) and there more sugars consumed (used in forming the acids) which also drives a less strong Maillard reaction.
So much to learn.
Addendum - Sorry if this is off topic but this thread really boosted my learning in a funny way. I did a search on "acid and Maillard reaction" and came across an article on the use of baking soda to speed the Maillard reaction. It does so because it raises the PH. Then, my little brain flashed - the banana muffins we baked yesterday browned very poorly (and the rise was just ok, not great). I went downstairs and asked my wife (in a, hopefully, safe and blame free way): "Did you add the baking soda to the flour yesterday in addition to the baking powder? Or, did you add baking powder only?" Ah hah, mystery solved.