I hope the necro isn't unwelcome, I just want to point out this fairly old script still appears to work just fine, and for its intended purpose. I'd just embarked in what looked like neutral terrain in the embark assistant, and had near dwarf utopia, i.e., a volcanic island (with a huge impractical peak), metals deep and shallow, a light aquifer (albeit salt water requiring desalination), a bit of stagnant ground water, flux, sand, and no neighbors at all.
It was called the "Land of Mortality" and it was in "the Ignoble Sea" but hey, it said it was neutral so whatever. Okay it's in a slightly bad neighborhood but tons of trees and no knife-eared hippies to whine about whatever we did with them, all the magma anyone could want, so what? Evil schmevil.
But then we started being incessantly pestered by undead albatrosses. They are absolutely helpless and easily wrecked, but why? Apparently while the ground is (relatively) neutral albeit with somewhat high savagery (on purpose), there is serious evil in the air.
[DFHack]# cat showbiomes.lua
cat is not recognized. Did you mean catsplosion?
[DFHack]# showbiomes
biomes found: 4
Biome reference: x: 59, y: 9, biome: OCEAN_TEMPERATE, Savagery: 62. Evilness: 94, found in the air only
Biome reference: x: 57, y: 7, biome: OCEAN_TEMPERATE, Savagery: 63. Evilness: 79, found in the air only
Biome reference: x: 58, y: 7, biome: OCEAN_TEMPERATE, Savagery: 55. Evilness: 71, found in the air only
Biome reference: x: 58, y: 8, biome: FOREST_TEMPERATE_CONIFER, Savagery: 59. Evilness: 60, found at ground level
Potential air biomes found:5
Biome reference x: 57, y: 8, biome: OCEAN_TEMPERATE, Savagery: 61. Evilness: 79
Biome reference x: 57, y: 9, biome: OCEAN_TEMPERATE, Savagery: 63. Evilness: 75
Biome reference x: 58, y: 9, biome: OCEAN_TEMPERATE, Savagery: 57. Evilness: 81
Biome reference x: 59, y: 7, biome: OCEAN_TEMPERATE, Savagery: 58. Evilness: 93
Biome reference x: 59, y: 8, biome: OCEAN_TEMPERATE, Savagery: 56. Evilness: 69
(Tbh what is on the ground is not that fantastic either.)