> 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.project/yarn.compiler.project.extensiondata.md).

# ExtensionData

Property in [Project](/3.1/api/csharp/yarn.compiler/yarn.compiler.project.md)

## Summary

Contains any data parsed from the source file that was not matched to a property on this type.

```csharp
public Dictionary<string, JsonElement>? ExtensionData { get; set; }
```