espocrm/application/Espo/Modules/Crm/Resources/metadata/entityAcl/Case.json

{
    "fields": {
        "inboundEmail": {
            "readOnly": true
        }
    },
    "links": {
        "inboundEmail": {
            "readOnly": true
        },
        "collaborators": {
            "readOnly": true
        }
    }
}