├─ {{FileSystemTreeEntry|icon=FST-Folder|type=FST-ReadOnly|name=custom}} - historical folder where the modded definitions were stored - no longer used.
├─ [[/def/]] - definitions of the game world, game objects, environment etc.
├── ├─ animatedmodel ├── ├─ camera ├── ├─ cargo ├── ├─ city ├── ├─ climate ├── ├─ company ├── ├─ country ├── ├─ desktop ├── ├─ ferry ├── ├─ initial_save ├── ├─ jobs ├── ├─ regional_settings ├── ├─ sign ├── ├─ stamp ├── ├─ vehicle ├── ├─ world
├─ {{FileSystemTreeEntry|icon=FST-Folder|type=FST-ReadOnly|name=dlc}} - shared models used by dlc such like "dead end" sign.
├─ {{FileSystemTreeEntry|icon=FST-Folder|type=FST-ReadOnly|name=effect}} - set of the graphical effects (shaders)