Examine source code of Toki Seme Context Menu

{
  "manifest_version": 2,
  "name": "Toki Seme Context Menu",
  "version": "1.0.3resigned1",
  "description": "Adds an option to translate selected text with Toki Seme.",
  "icons": {
    "48": "icon48.png"
  },
  "permissions": [
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "index.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{215d6b21-e2d4-4e31-ab62-1b974c1f448b}"
    }
  }
}