Examine source code of Snipper

{
  "manifest_version": 2,
  "name": "Snipper",
  "version": "0.1.1",
  "description": "Save highlighted text from any webpage.",
  "author": "Heiko",
  "browser_specific_settings": {
    "gecko": {
      "id": "{e8f2c4a1-9b3d-4f5e-a6c7-8d9e0f1a2b3c}",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "contextMenus",
    "storage",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  }
}