After an embarrassing long time of trying to understand them, I now know how Descriptor Mapper s work!!!!!

What are Descriptor Mappers for?

They are a wrapper to your descriptors, mostly called "Effect_" etc that override the way the game automatically displays the Property Effects in those descriptors.

Lets get an example.

Effect_Exploitation_Prairie's Descriptor is

Keep in mind that all Effects, and the individual Property Effects inside them, are numbered starting with 0.

The second Property effect increases the vision range of any district exploiting the tile by 1. But that information isn't needed by the player as is just a core mechanic. so we want to hide it from them. In comes the Descriptor Mapper with the same name as the Descriptor.

First, we select the Property Effect we want to hide:

Effect Index                     0

Property Effect Index     1

Then just tick

Hide Property Effect []

Done. It will no longer be automatically converted into part of the tooltip.

I haven't yet gone digging through the "solve RPN Formula" Or the "Parameter Flags", but I know you can use the "Effect Localization" to set your own custom display for that property effect.

Hope this helps other people baffled by the same things.

Thanks for the knowledge, it will be quite usefull