code: async function() {
        let contrib_json_path = this.getContribFileName();
        if (!await fs.existsAsync(contrib_json_path)) {
          return {
            version: qx.tool.cli.ConfigSchemas.lockfile.version,
            libraries: []
          };
        }
        return qx.tool.compiler.utils.Json.loadJsonAsync(contrib_json_path);
      }
docs: Returns the library list from the contrib file
  @return {Object}