Function crit_chance_scaled_spell_percent 

pub fn crit_chance_scaled_spell_percent(
    terms: &[CritChanceScaledCritDamage],
    target_class_set: i32,
    target_class_masks: [i32; 4],
    target_labels: &[i32],
) -> f64

Percentage of the caster’s critical strike chance the terms add to one spell’s crit bonus.

Only the spell axis is per-spell; the player axis is school-filtered at damage time instead.