Examine source code of Everything bar

{
  "manifest_version": 2,
  "name": "Everything bar",
  "version": "1.1",
  "description": "A custom searchable tab button for Firefox.",
  "permissions": [
    "tabs",
    "sessions",
    "history",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "e1c63f75-bea6-4499-9fb2-29b54539c301@example.com"
    }
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+E",
        "mac": "Command+Shift+E"
      },
      "description": "Open Tab Search Popup"
    }
  }
}