Examine source code of Link Transformer

{
  "manifest_version": 2,
  "name": "Link Transformer",
  "version": "1.0",
  "description": "Transforms right-clicked links by removing 'origin' and adding 'authuser=4'.",
  "permissions": [
    "contextMenus",
    "activeTab",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7b8f1173-ec24-49b6-be37-e75e275796cf}"
    }
  }
}