Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Install the Localization package (com.unity.localization)
3. Open the Project Settings window (Edit > Project Settings)
4. Open the Localization tab in the Project Settings window
5. Press the "Create" button
6. Press the "Save" button
7. Observe the Console window

Actual results: "The type Unity.Localization UnityEngine.Localization.SmartFormat.Extensions.ListFormatter is being serialized by [SerializeReference]" warning is thrown

Expected results: No warnings are thrown

Reproducible with versions: 1.5.9 (6000.4.0a1, 6000.4.0a5, 6000.5.0a1)

Not reproducible with versions: 1.5.9 (6000.0.62f1, 6000.2.12f1, 6000.3.0f1)

Tested on (OS): MacOS Silicon Tahoe 26.0.1