# IResourceCollectionExtension

> Marks a serializable class that attaches tool-specific data to a ResourceTableCollection.

## Definition

* **Type:** Interface
* **Namespace:** [Unity.Localization.Editor](/engine/6000.7/script-reference/unity/localization/editor.md)
* **Assembly:** UnityEditor

```csharp
public interface IResourceCollectionExtension
```

## Remarks

An extension travels with the collection asset through [ResourceTableCollection.AddExtension](/engine/6000.7/script-reference/unity/localization/editor/resourcetablecollection/addextension.md) and is stored by reference, so any serializable implementation works, for example the connection settings for an external translation service. Read one back with [ResourceTableCollection.GetExtension](/engine/6000.7/script-reference/unity/localization/editor/resourcetablecollection/getextension.md).