Here's a nearly-readable version in .xls format. Here are the fields explained:
How to read it:
The Path and Rarity columns are pretty self-explanatory, and match to the number values used in the modding manual.
Each site has up to 5 powers, each of which has an argument.
Power1 corresponds to Argument1, Power2 corresponds to Argument2, and so forth.
The codes for powers and their arguments are (unused powers are not noted, but may do things - for example, I bet there's a power that generates temples):
Powers 1-8 are *gem income* - these are off by 1 from the ordinary path numbers (so fire is 1 instead of 0, etc.). Argument is the number of gems.
Power 10 was probably once extra-resources in capital. May not do anything now?
Power 11 is a recruitable troop. Argument is unit #.
Power 12 is a recruitable commander. Argument is unit #.
Power 13 is gold income. Argument is amount of gold.
Power 14 is resource income. Argument is number of resources.
Power 15 generates labs when found. Argument is just 1.
Power 16 generates temples when found, but is not used. Argument would presumably be 1 if it existed.
Power 17 makes fortresses when found. Argument is fort #.
Power 18 is enter-to-summon - it's repeated for each unit that appears. The type of mage automatically matches the type of site. Argument is unit #.
Power 19 is unrest adjustment - argument gives amount. Negative numbers increase unrest. Note that negative numbers are represented as very bug numbers in the spreadsheet (sorry).
Power 20 is supplies adjustment. Argument gives amount.
Power 21 is spreads disease. Argument is percent chance of disease per turn in the province.
Power 22 is enter for (argument) experience points.
Power 24 is horrormarking. Argument is percent chance of horrormark per turn in the province.
Power 29 is capital-only-unit. Argument is unit #.
Power 30 is capital-only-commander. Argument is unit #.
Power 31 is increase scales:
Argument 0 -> Order
Argument 1 -> Productivity
Argument 2 -> Heat
Argument 3 -> Growth
Argument 4 -> Fortune
Argument 5 -> Magic
Power 32 is *decrease scales*. Same arguments.
Power 57 is enter to summon void monsters. Argument is always 20 - might be base chance of success.
Power 60+X is a bonus for a given school of magic. Argument is %.
Power 67 is holy power. Argument is % chance of each undead being hit by AN10. "Your undead units in <province name> are being killed by a holy force native to this province."
Power 68 is holy fire. Argument is % chance of each undead or demon being hit by AN10. "Your undead and demonic troops in <province name> are being hit by holy fire".
Power 70 is probably remove battle afflictions. Argument would presumably be % chance.
Power 71 is curse. Once again, argument is % chance per unit per turn.
Power 72 is enter-to-scry.
Power 192 is enter for adventure. Edi speculates that the argument is % chance of getting anything useful.
D'oh! I had two field lengths wrong!
Replaced with a new attachment.