Steps: 1. Right-click the toolbar icon → Manage Extension → Preferences (Options). Region = Global, paste the token, Save. 2. Open https://mail.google.com and open any email. 3. Open the SmartReplyAssistant sidebar (toolbar sidebar button or Ctrl+Shift+U) — it summarizes the email and drafts a reply.
Note: this is a Firefox build (sidebar_action). The source is plain, unminified JavaScript — no build step, the submitted files are the original source.
