docs: function findForBook(book) {
      return timing.measure(
          'plugins.findForBook',
  
          Promise.all([
              findInstalled(locateRootFolder()),
              findInstalled(book.getRoot())
          ])
  
          // Merge all plugins
          .then(function(results) {
              return Immutable.List(results)
                  .reduce(function(out, result) {
                      return out.merge(result);
                  }, Immutable.OrderedMap());
          })
      );
  }