Examine source code of Tab Control Manager

{
  "manifest_version": 2,
  "name": "Tab Control",
  "version": "0.4.2",
  "description": "View and control tabs the way I want",
  "browser_specific_settings": {
    "gecko": {
      "id": "tabcontrol-addon@sandbox0.com"
    }
  },
  "icons": {
    "48": "icons/launcher-48.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/launcher-48.png"
    },
    "default_title": "TabControl",
    "browser_style": true
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": false,
    "chrome_style": false,
    "open_in_tab": true
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "storage"
  ],
  "background": {
    "page": "index.html"
  },
  "commands": {
    "goto-tab-1": {
      "suggested_key": {
        "default": "Ctrl+1"
      },
      "description": "Go to 1st tab"
    },
    "goto-tab-2": {
      "suggested_key": {
        "default": "Ctrl+2"
      },
      "description": "Go to 2nd tab"
    },
    "goto-tab-3": {
      "suggested_key": {
        "default": "Ctrl+3"
      },
      "description": "Go to 3rd tab"
    },
    "goto-tab-4": {
      "suggested_key": {
        "default": "Ctrl+4"
      },
      "description": "Go to 4th tab"
    },
    "goto-tab-5": {
      "suggested_key": {
        "default": "Ctrl+5"
      },
      "description": "Go to 5th tab"
    },
    "goto-tab-6": {
      "suggested_key": {
        "default": "Ctrl+6"
      },
      "description": "Go to 6th tab"
    },
    "goto-tab-7": {
      "suggested_key": {
        "default": "Ctrl+7"
      },
      "description": "Go to 7th tab"
    },
    "goto-tab-8": {
      "suggested_key": {
        "default": "Ctrl+8"
      },
      "description": "Go to 8th tab"
    },
    "goto-last-tab": {
      "suggested_key": {
        "default": "Ctrl+9"
      },
      "description": "Go to last tab"
    }
  }
}