Examine source code of quick-cleaner

{
  "description": "Clears History & Downloads",
  "manifest_version": 2,
  "name": "quick-cleaner",
  "version": "2.1",
  "icons": {
    "1": "icons/cleaner.ico"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/cleaner.ico",
    "default_title": "Quick Cleaner"
  },
  "permissions": [
    "browsingData",
    "notifications",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c09e25f3-49cc-433c-b565-e7bc34a196fe}"
    }
  }
}