Examine source code of ChecksumCalculator

{
  "manifest_version": 3,
  "name": "ChecksumCalculator",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "version": "2.3",
  "icons": {
    "48": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "Options/options.html",
    "browser_style": true
  },
  "host_permissions": [
    "*://*/*"
  ],
  "permissions": [
    "contextMenus",
    "storage"
  ],
  "optional_permissions": [
    "privacy"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{bcf81066-a6c6-47c0-8eb9-43051fe7b09e}",
      "strict_min_version": "42.0"
    }
  }
}