To me that's a major find Keith, thanks!
Do you know what the 4 lines correspond to? like light, medium, heavy rain?
Also, in my file, that I don't think having ever modded, I found those values were 5% higher like this:
<mapping ai_variable="wet_weather_ability" characteristic="wet_weather_ability" type="NEFloat" value="1.0" num_limits="4">
<limit difficulty="0.0" characteristic_value="0.0">
0.95</limit>
<limit difficulty="0.0" characteristic_value="1.0">
1.0</limit>
<limit difficulty="1.0" characteristic_value="0.0">
0.95</limit>
<limit difficulty="1.0" characteristic_value="1.0">
1.0</limit>
</mapping>
Isn't this strange?