Show sources for tile values

I don't believe there is any way to see the calculation of the tile yields, but its generally not that hard to figure it out yourself.

There is a handy page here that describes all the details on tile yields, but the general rule of thumb is:

• If it's green it gives more food
• If it's a hill it gives more production
• If it's got some other feature on it then it gets an additional gold/food/production bonus depending on the resource
• If it gives something that is not gold/food/production then its getting a bonus applied from either a natural wonder (always within one tile), a wonder (always in the city), or a religion/pantheon (you can check for this yourself.

That's pretty much all the possible inputs for tile yield calculations.