If we try to assign in any plugin class this property, we get the compiller error, example:
public void PreProcess(ISettings settings)
        {
....
                if(settings.AdditionalReportFiles == null)
                    settings.AdditionalReportFiles = new List<string>();

Error	1	Property or indexer 'NCrash.ISettings.AdditionalReportFiles' cannot be assigned to -- it is read only	C:\Users\igor\Documents\GitHub\NCrash-1\NCrash\Plugins\ScreenShotWriter.cs	111	21	NCrash