Almost everything should be self explanatory after examination of any mesh file in text form except for the following:
This tells the engine whether the mesh already has valid tangents or not. If a mesh doesn’t provide valid tangents they will be generated by DirectX. This is not preferred as 3D packages tend to do a better job.
<FRONT,BACK,LEFT, RIGHT,UP,DOWN>: These indice lists help the engine optimize a number of operations (in particular weapons fire) and each list is a sample of indices that reference vertices with normals that are within some min angle of the direction indicated and are sorted by distance to the origin of that direction. The origin of that direction is defined as the unit normal vector of that direction * mesh radius and the min angle is ((90 + 45) / 2) degrees.
The text versions of all mesh files are found in <Reference Data>\Mesh.