It could have stuff like:
Site name
Magic type
Site level (0-4)
Site description (pretty pleaaaase?)
Gem income
Gem type
If gem type is random: Bloodslaves yes/no
Gem amount
Income not tied to Richness/Income tied to Richness
Income tied to Scale (
)
Income tied to Season
Gold bonus
Resource bonus
Gives structure
Alters scale in the province
Allows construction of unit
Site spreads diseases
Site spreads 'abilities'/afflictions (curse, horror mark)
Site spreads unrest
Site damages unit type (demons, undead, angels, magic etc.)
Site causes monster attacks
Any commander can enter/only specific mage can enter
Enter to explore a dungeon
Enter to combat monsters to de/activate further site abilities
Enter to summon unit/s
Enter to gain experience
Enter to cast a spell
Effect is continous/is not (does the mage stop casting the spell or not)
Times commander can enter (1, 5, 10 etc.)
Site can/cannot be exhausted (does other site functions stop when the effect charges stop)
Void gate mechanic yes/no
Summoning description ("enter to summon demons" etc)
Summonable units
Unit power tier (Imp - tier 3, Spine Devil - tier 2 etc.)
Failure effects (attacked, death, insanity, blindness, disease etc)
Summoning skill affects (and how much?)
Summoning time (3 turns, tier * 2 and such)
Examples
Summer Stone
sitename: "Summer Stone"
sitetype: "Fire"
sitelevel: 1
sitedscr: "A large standing stone filled with glowing runes of summer"
gems: yes
gemtype: "Fire"
gems_season: Spring: 2
Summer: 3
Fall: 2
Winter: 0
Pool of Sorcery
sitename: "Pool of Sorcery"
sitetype: "Astral"
sitelevel: 1
sitedscr: "Hidden in a deep forest, the pool radiates powerful and eeries energies."
gems: yes
gemtype: "Sorcery random"
bloodslv: No
gem_amount: 1
gem_scale: magic 1: +1
magic 2: +2
Valley of Rusty Mists
sitename: "Valley of Rusty Mists"
sitetype: "Earth"
sitelevel: 0
sitedscr: "A well known but avoided valley. There are no plants to be seen and the soil is covered in rusty mud. Every morning ominous yellow clouds seep from the ground. Locals tell that this mist will turn weapons into rust swiftly..."
gems: yes
gemtype: "Earth"
gem_amount: 1
gemtype: "Water"
gem_amount: 1
spreads_abl: "Destruction"
damages: Constructs
Tents of the Lost Tribe
sitename: "Tents of the Lost Tribe"
sitetype: "Astral"
sitelevel: 1
sitedscr: "A great tribe whose shamans practiced soul-traveling with the aid of magic herbs once lived here. Now they are gone, but their tents and a stock of magic herbs are still here."
gems: yes
gemtype: "Astral"
gem_amount: 1
gemtype: "Nature"
gem_amount: 1
can_enter: yes
mage_only: yes
casts_spell: "Astral Probing"
charges: 5
site_exhausts: yes
Mesa of Lost Freaks
sitename: "Mesa of Lost Freaks"
sitetype: "Blood"
sitelevel: 0
sitedscr: "A cavernous mesa has been infected by runaway experiments of some blood mage. Now they terrorize the locals with their raid, but maybe they can be pressed into service with force..."
gems: yes
gemtype: "Blood"
gem_amount: 1
gemtype: "Nature"
gem_amount: 1
site_unrest: 15
monster_attacks: yes
monster_commander: Ettin
monsters_1: 20 Tentacled Yokels
recruit: "Tentacled Yokel"
"Yokel Commander"
can_enter: yes
mage_only: no
fight_monsters: yes
monster_commander: Ettin
monsters_1: 20 Tentacled Yokels
activate: gems
enter_summon
recruit
deactivate: site_unrest
monster_attacks
enter_summon: yes
3 x Tentacled Yokel