I am a little confused by this particular tag. Is it only for the controlling Civ or is it global in that all Civ's get the modification?

In the event of the latter, how does one set it such that only the controlling civ get the bonus across all cities and continents?

Bit of an update on my query.

I have added to the Pyramid, GlobalYieldModifiers tag to increase food, production, and gold.

Comparatively, I have seen a huge increase for my Civ. However, I am seeing similar effects on other Civs - I think.

I am playing a Deity/Marathon/Cheats game at the moment, and after 50 or so turns, the visible AI Civs have at least a dozen defending units, and several roaming units compared to earlier games where I may have seen a scout or two, but not roaming warriors.

Bit of an update on my query.

I have added to the Pyramid, GlobalYieldModifiers tag to increase food, production, and gold.

Comparatively, I have seen a huge increase for my Civ. However, I am seeing similar effects on other Civs - I think.

I am playing a Deity/Marathon/Cheats game at the moment, and after 50 or so turns, the visible AI Civs have at least a dozen defending units, and several roaming units compared to earlier games where I may have seen a scout or two, but not roaming warriors.

That affect will be added to every city. So, if you give it values of 1,2 and 3, every city owned by the player who has that building (or wonder) will get an extra 1 food, two hammers and three gold per turn. It shouldn't affect other civs.