Examine source code of Ethereum Gas Watcher

{
  "manifest_version": 2,
  "name": "Ethereum Gas Watcher",
  "version": "1.0",
  "author": "Matthias Nadler",
  "description": "Monitor Ethereum Gas Prices and set notifications",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "64": "icons/icon64.png",
    "134": "icons/icon134.png"
  },
  "permissions": [
    "storage",
    "alarms",
    "notifications"
  ],
  "browser_action": {
    "default_icon": "icons/icon32.png",
    "default_title": "Ethereum Gas Watcher",
    "default_popup": "src/popup.html"
  },
  "background": {
    "scripts": [
      "src/background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "ethereum_gas_watcher@matnad.eth"
    }
  }
}