gistfile1.txt

*** Search: addEnginesFromExtension: Failed to install [email protected]: "The extension has not been initialized."

thrown from: 

    await extension.getLocalizedManifest(locale)

Which is called from startup by:

      for (let [id, localeMap] of this._extensions) {
        let policy = WebExtensionPolicy.getByID(id);
        if (policy) {
          LOG("_loadEngines: Found previously installed extension");
          await this.addEnginesFromExtension(policy.extension);