rmSummarySection.js

VSS.require([
  'ReleaseManagement/Core/RestClient'
], function(RMRestClient) {
  var client = RMRestClient.getClient();

  var config = VSS.getConfiguration();
  var projectId = VSS.getWebContext().project.id;

  config.onReleaseChanged(function(release) {
    client.getReleaseWorkItemsRefs(projectId, release.id).then(
      function(refs) {
        console.log('work item refs:', refs);
      },
      function(error) {
        console.log(error);
      }
    );
  });

  VSS.notifyLoadSucceeded();
});