code: function filterForKeyword(extensionList, word) {
              var filteredList = [];
              extensionList.forEach(function (id) {
                  var entry = self._getEntry(id);
                  if (entry && self._entryMatchesQuery(entry, word)) {
                      filteredList.push(id);
                  }
              });
              return filteredList;
          }
docs: Takes 'extensionList' and returns a version filtered to only those that match 'keyword'