Examine source code of Decrypt Selection

{
  "manifest_version": 2,
  "name": "Decrypt Selection",
  "version": "1.0",
  "description": "Decrypt selected text and view as JSON",
  "permissions": [
    "contextMenus",
    "activeTab",
    "clipboardRead"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "decrypt-selection-v2@example.com"
    }
  },
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Расшифровать из буфера",
    "default_icon": {
      "16": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    }
  }
}