Examine source code of BLOSSOM ADDON

{
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "0.1.2",
  "default_locale": "en",
  "icons": {
    "48": "icons/icon48.png"
  },
  "permissions": [
    "webRequest",
    "http://*/*",
    "https://*/*",
    "*://*.google.com/"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png"
    }
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  }
}