code: function nameSpacedDefine(nameSpace, id, deps, callback) {
    // only add name space for modules in user space
    // also skip any ext: plugin (a dumber-module-loader feature)
    if (currentSpace === userSpace && id.slice(0, 4) !== 'ext:') {
      const parsed = parse(id);
      userSpace.define(parsed.prefix + nameSpace + '/' + parsed.bareId, deps, callback);
    } else {
      currentSpace.define(id, deps, callback);
    }
  }
docs: Special named spaced define Designed to load runtime extensions