> For the complete documentation index, see [llms.txt](https://docs.yarnspinner.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.yarnspinner.dev/3.1/api/csharp/yarn.compiler/yarn.compiler.declaration/yarn.compiler.declaration.externaldeclaration.md).

# ExternalDeclaration

Field in [Declaration](/3.1/api/csharp/yarn.compiler/yarn.compiler.declaration.md)

## Summary

The string used for [SourceFileName](/3.1/api/csharp/yarn.compiler/yarn.compiler.declaration/yarn.compiler.declaration.sourcefilename.md) if the Declaration was found outside of a Yarn source file.

```csharp
public const string ExternalDeclaration = "(External)";
```