UpdateMask

Array of field paths specifying which fields to update. Uses dot notation for nested fields (e.g., "config.revision", "metadata.tags"). **Field Path Rules:** - Use dot notation for nested objects: `parent.child.field` - Escape special characters: `field\.with\.dots`, `field\:with\:colons` - Array elements not directly addressable - Object names can be specified directly (e.g., "config.content.read.objects.contacts") - The * operator in paths like "config.content.read.objects.*" allows you to specify any object name - Example: "config.content.read.objects.*" pattern allows "config.content.read.objects.contacts", "config.content.read.objects.leads", etc.