Modifier
Learning
learning_modifier_with_offset
Learning (modifier ID learning_modifier_with_offset) is a named modifier in Crusader Kings III. It gives County Fertility Growth +2%. No add_…_modifier command in common/, events/ or history/ adds it. Patch 1.20.1.2, from game/common/modifiers/00_basic_modifiers.txt.
Effects
Where the game adds it
No add_…_modifier command in common/, events/ or history/ adds it.
Source: game/common/modifiers/00_basic_modifiers.txt (line 44), the English localisation (learning_modifier_with_offset, learning_modifier_with_offset_desc) and every add_…_modifier / remove_…_modifier in common/, events/ and history/, Crusader Kings III 1.20.1.2.