Examine source code of Donate and Smile

{
  "manifest_version": 2,
  "name": "Donate and Smile",
  "version": "0.2.1resigned1",
  "author": "Sublime Fund Inc.",
  "description": "Automatically redirect from Amazon to AmazonSmile to support your favorite charity when you shop.",
  "homepage_url": "https://sublimefund.org",
  "applications": {
    "gecko": {
      "id": "donate-and-smile@sublimefund.org"
    }
  },
  "icons": {
    "16": "images/icon-16.png",
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "images/icon-128.png",
    "default_popup": "toggle-popup.html"
  },
  "options_ui": {
    "browser_style": true,
    "page": "toggle-options.html"
  },
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "https://*.amazon.com/"
  ]
}