Hi, awesome work!! I love the foliage, it looks really nice :) I also like your workflow, offers more possibilities than handpainting like some of the old models. 0 A.D. uses .dae files, which is not supported by blender since version 5 anymore. I will figure it how to exports your models and make a mod for it, so we can see how it looks ingame. Until then, some things that came to my mind on a first glance: 1. Faces are shown in 0 A.D. only from one side. By activating backface culling or face orientation in the top right corner in the viewport you can see which face would be seen from each perspective. If you want to show faces from both side, you'd have to duplicate it, move it a little and flip the normal (Alt-N). 2. Everything should use just one texture. So ideally the tree trunk should be somewhere on the foliage texture too. 3. All meshes in 0 A.D. usually expand a little below ground for uneven terrain. I couldn't reproduce the problem with the normals, looks fine on my pc. For an olive orchard would be cool to display some black olives (the fruits) on it, so the player can harvest them similar to the berry bushes. But that's a gameplay decision I'll leave to someone else :D

I cannot check all zips you distribute. If you clone (or download) your repo, you'll have the correct file structure. On a side note this situation is NOT an isolated instance of troubles caused by compatibility check doing things that seems outside of its scope. The folder name, or the file structure shouldn't be taken into account for compatibility check. The mod.json should contain the only data used to determine compatibility, any other additional rule is likely just going to create pain for modders.

Isn't the formula simply  DMG*0.9^Resistance  

You need to import the functions you are using something like import { addAnimals, addBerries, addBluffs, addDecoration, addForests, addHills, addLayeredPatches, addMetal, addStone, addStragglerTrees, createBluffsPassages, markPlayerAvoidanceArea } from "maps/random/rmgen2/gaia.js";

the image is this: