Examine source code of ChartPop

{
  "manifest_version": 2,
  "name": "ChartPop",
  "version": "1.1",
  "description": "Stop opening new tabs! Instantly see stock prices and mini charts by hovering over tickers on any webpage.",
  "permissions": [
    "activeTab",
    "storage",
    "https://query1.finance.yahoo.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "chartpop@simul8or.com"
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    },
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  }
}