code: def render_group_manifests(self):
          
          if not self.dj.dock_json_has_plugin_conf('postbuild_plugins', 'group_manifests'):
              return
  
          push_conf = self.dj.dock_json_get_plugin_conf('postbuild_plugins',
                                                        'group_manifests')
          args = push_conf.setdefault('args', {})
          # modify registries in place
          registries = args.setdefault('registries', {})
          placeholder = '{{REGISTRY_URI}}'
  
          if placeholder in registries:
              for registry, secret in zip_longest(self.spec.registry_uris.value,
                                                  self.spec.registry_secrets.value):
                  if not registry.uri:
                      continue
                  regdict = registries[placeholder].copy()
                  regdict['version'] = registry.version
                  if secret:
                      regdict['secret'] = os.path.join(SECRETS_PATH, secret)
                  registries[registry.docker_uri] = regdict
              del registries[placeholder]
  
          self.dj.dock_json_set_arg('postbuild_plugins', 'group_manifests',
                                    'group', self.spec.group_manifests.value)
          goarch = {}
          for platform, architecture in self.platform_descriptors.items():
              goarch[platform] = architecture['architecture']
          self.dj.dock_json_set_arg('postbuild_plugins', 'group_manifests',
                                    'goarch', goarch)
docs: Configure the group_manifests plugin. Group is always set to false for now.