AssetDatabase.ClearImporterOverride

Сбрасывает переопределение импортёра для ассета.

using UnityEngine;
using UnityEditor;
using UnityEditor.AssetImporters;
using UnityEngine.Assertions;

public class AssetDatabaseExamples : MonoBehaviour
{
    [MenuItem("AssetDatabase/Example Importer Actions")]
    static void AllImporterActions()
    {
        //This sets CubeImporter to be used for the asset
        AssetDatabase.SetImporterOverride<CubeImporter>("Assets/CompanionCube.cube");
        Debug.Log("New importer: " + AssetDatabase.GetImporterOverride("Assets/CompanionCube.cube"));

        //This clears importer override and sets it to null
        AssetDatabase.ClearImporterOverride("Assets/CompanionCube.cube");
        Assert.IsNull(AssetDatabase.GetImporterOverride("Assets/CompanionCube.cube"));
    }
}