Modding Tutorials/Folder structure

In this tutorial you will explore Rimworld's folder structure.

In your Rimworld install directory, you can find three folders; /Mods/ , /RimWorld******_Data/ and /Source/ ; a Readme and Version text file and your RimWorld******.exe file.
We'll focus on the folders, since the files are pretty self explanatory.

Mods

The Mods folder contains a /Core/ folder with most if not all XML files used by Rimworld.

This folder is also the place you install any mods you download.

Mod folder structure

Main article: Modding Tutorials/Mod folder structure

The mods inside /Mods/ may contain the following folders:

Folder	Contents	Description
About	About.xml and Preview.png	These files are used in the in-game mods list. They contain some info about the mod and an unformatted text description.
Assemblies	Custom .DLL files	Mods with custom C# code have a .DLL file in this folder.
Defs	All defs	All XML code is stored in this folder, usually further categorized in subfolders and -files.
Languages	All translations	Every language file contains a /DefInjected/ folder with a translation for everything in the game.
Sounds	All sounds	Even though the main game's sounds are stored in compressed resource files, mods might use a folder for them.
Source	/Assemblies/ source code	Mods with an /Assemblies/ folder might store source code for the C# code in here.
Textures	All textures	The main game uses compressed resource files to store textures, but most mods store textures here.

RimWorld******_Data

This folder contains a few files which are important for the base game but not necessarily important for modding it, such as; .DLL's which contain the game code, compressed resource files containing the game graphics and audio, several files automatically generated by Unity which contain settings and such, a copy of Mono and a Steamworks .DLL.

What you might at one point be interested in are the Managed/ folder and output_log.txt, which contain .DLL's required for writing custom C# code and a more detailed version of the game's debug log.

Source

This folder contains a small amount of the game's C# source code. These can be seen as tiny examples someone might use to get started with C# modding.
Anyone interested in bigger chunks of the source code is better off decompiling it by themselves.