The default Lit Material is editable and throws an immutable package warning when edited in the Light Explorer's Static Emissives tab

Steps to reproduce:

1. Create a new project using the Universal 3D template
2. In the Hierarchy, add a "Sphere" GameObject (or any other GameObject with default Lit Material)
3. In the Inspector, in the Lighting foldout, enable "Contribute Global Illumination" property
4. Go to Window > Rendering > Light Explorer
5. Navigate to "Static Emissives" tab
6. Observe the "Lit" Material is shown
7. Edit any of its properties and Save
8. Observe the Console

Actual results: The default Lit Material is editable and "The following asset(s) located in immutable packages were unexpectedly altered..." warning is shown after editing

Expected results: The default Lit Material should not be editable or shown at all

Reproducible with versions: 6000.7.0a4

Not reproducible with versions: 6000.5.7f1, 6000.6.0b7, 6000.7.0a3 (Lit Material does not appear in the list)

Tested on (OS): macOS 26.5

Notes:

• The same Material is read-only when selected in the Inspector. Only the Light Explorer allows its properties to be changed.