Examine source code of ETH Gas Price

{
  "name": "ETH Gas Price",
  "description": "Ethereum gas price tracker",
  "version": "1.4.0",
  "manifest_version": 2,
  "icons": {
    "16": "icons/icon-16x16.png",
    "48": "icons/icon-48x48.png",
    "128": "icons/icon-128x128.png"
  },
  "options_ui": {
    "page": "www/index.html#/options",
    "browser_style": true,
    "open_in_tab": true
  },
  "browser_action": {
    "default_title": "Ethereum Gas Price",
    "default_popup": "www/index.html#/popup"
  },
  "background": {
    "scripts": [
      "www/js/bex-background.js",
      "js/background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "www/js/bex-content-script.js",
        "js/content-script.js"
      ],
      "css": [
        "css/content-css.css"
      ]
    }
  ],
  "permissions": [
    "<all_urls>",
    "storage"
  ],
  "web_accessible_resources": [
    "www/*",
    "js/*",
    "css/*",
    "<all_urls>"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self';"
}