Desync debugging
OpenTTD Development Documentation
External Links

OpenTTD GitHub
Contributing to OpenTTD - guidelines
OpenTTD Doxygen

General Reference

Coding style
Compiling OpenTTD
Debugging
Add a setting
Add a squirrel function
Understanding the SaveGame handler
Bumping the savegame version
Doing an OpenTTD release

Language and Strings

Manual of style
Format of langfiles
Using OpenTTD strings
List of special strings

Window System

Using the window system
Colour codes that exist in OpenTTD
Adding a text box
Understanding the widget focus system
GUI style guide

Multiplayer

The OpenTTD TCP protocol
The OpenTTD UDP protocol
Debugging desyncs
Server Admin Port development

Ingame Console

The console window
Console commands
Console variables
Using console scripting
Adding functions/commands to the console
Adding variables to the console
Console development history

Content APIs (modding frameworks)

Graphics and similar (NewGRF)
AI framework (NoAI)
GameScript framework (NoGO)

Other Reference

Map array (landscape grid)
Vehicles
Pathfinding
Train acceleration
Sound IDs

Desyncs

OpenTTD GitHub docs contain a guide to desyncs.

How to gather desync data

In order to fix a desync, one needs playback data. Only server admins can gather those and their help is needed as they need to enabled desync debugging on their servers. Without these desync debugging data one has nearly no chance to find and fix these bugs. This is how you can gather these necessary data and help us pin-point and ultimately fix the problem:

Anything less will likely not fix the desync issue nor help finding it. Thus if you are a server admin and want to see them gone: enable desync debugging on *your* server and gather the data! Don't wait for anyone else - chances are slim there will be, especially as some desyncs might need the specific combination of settings and / or NewGRFs which only you use on a server.