From Onset Developer Wiki

This describes the game console parameters which can be set in Steam.

Switch Description
-dev Enables the development mode. Currently this enables file logging of Lua errors and more. File is to be found under %appdata%\..\Local\Onset\Saved\Logs\DevLog.txt
-cefdebug= Specifies a different CEF remote debugging port (Default port is 9222).
-ConnectAddress= Connects to a specific server by ip or hostname.
-ConnectPort= Specifies connect port.
-ConnectPassword= Specifies server password.
-dx12, -dx11 (default) Specifies DirectX RHI version.
-windowed Starts game in windowed mode.
-fullscreen Starts game in fullscreen mode.

Client Folder Paths

Settings save files %appdata%\..\Local\Onset\Saved\SaveGames
Game logs (Requires dev mode) %appdata%\..\Local\Onset\Saved\Logs
Crash dumps %appdata%\..\Local\Onset\Saved\Crashes