About the BizTalk Orchestration Engine
At run time, the BizTalk Orchestration Engine executes XLANG/s files that are produced by BizTalk Orchestration Designer. Orchestration Designer is a rich graphical tool for visually designing business processes. It generates XLANG/s files that have an .odx extension and contain additional visualization information in their headers and custom attribute information in their bodies.
XLANG/s can be viewed as a messaging language with some of the expression capabilities of C#.
The primary functions of the orchestration engine are:
Hosting the .NET components
Large message support