anchor.diff:      : ISA '=' 'XCConfigurationList' ';'
       ;
   
  +isa_xc_remote_swift_package_reference
  +    : ISA '=' 'XCRemoteSwiftPackageReference' ';'
  +    ;
  +
  +isa_xc_swift_package_product_dependency
  +    : ISA '=' 'XCSwiftPackageProductDependency' ';'
  +    ;
  +
   isa_xc_version_group
       : ISA '=' 'XCVersionGroup' ';'
       ;
  
positive.code:       '}' ';'
      ;
  
  xc_version_group
      : REFERENCE '=' '{'
          isa_xc_version_group
  
negative.code:         pbx_variant_group_section?
          xc_build_configuration_section
          xc_configuration_list_section
          xc_remote_swift_package_reference_section?
          xc_swift_package_product_dependency_section?
          xc_version_group_section?
        '}' ';'
      ;
  