code: function initKarmaParallelizer(root, karma, shardIndexInfoMap) {
    var idParamExtractor = /(\?|&)id=(\d+)(&|$)/;
    var matches = idParamExtractor.exec(parent.location.search);
    var id = (matches && matches[2]) || null;
  
    if (
      !id ||
      !shardIndexInfoMap.hasOwnProperty(id) ||
      !shardIndexInfoMap[id].shouldShard
    ) {
      /* eslint-disable-next-line no-console */
      console.warn(
        'Skipping sharding. Could not find karma-parallel initialization data.'
      );
      return;
    }
  
    var shardIndexInfo = shardIndexInfoMap[id];
    var strategy = overrideSuiteStategy(getSpecSuiteStrategy(shardIndexInfo));
    var fakeContextStatus = createFakeTestContext(root, strategy);
  
    var origStart = karma.start;
    karma.start = function() {
      fakeContextStatus.beforeStartup();
      origStart.call(this);
    };
  }
docs: This file gets loaded into the executing browsers and overrides the `describe` functions