Examine source code of Draft Caddy

{
  "manifest_version": 2,
  "name": "Draft Caddy",
  "version": "2.91",
  "description": "Draft data and free tools for Underdog and best ball",
  "icons": {
    "16": "EGS-onWhite-16.png",
    "48": "EGS-onWhite-48.png",
    "128": "EGS-onWhite-128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "EGS-onWhite-16.png",
      "48": "EGS-onWhite-48.png",
      "128": "EGS-onWhite-128.png"
    },
    "default_popup": "popup.html",
    "default_title": "Draft Caddy"
  },
  "options_page": "options.html",
  "content_scripts": [
    {
      "css": [
        "jquery.powertip-dark.css"
      ],
      "js": [
        "content.js"
      ],
      "matches": [
        "*://*.underdogfantasy.com/*",
        "*://*.underdogsports.com/*",
        "*://*.drafters.com/*",
        "*://*.draftkings.com/*",
        "*://*.draftkings.co.uk/*",
        "*://*.fanduel.com/*"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "applications": {
    "gecko": {
      "id": "{3a2e501d-4819-4797-abac-7e56f7ab613f}",
      "strict_min_version": "58.0"
    }
  },
  "permissions": [
    "tabs",
    "storage",
    "*://*.underdogfantasy.com/*",
    "*://*.underdogsports.com/*",
    "*://*.drafters.com/*",
    "*://*.draftkings.com/*",
    "*://*.draftkings.co.uk/*",
    "*://*.fanduel.com/*",
    "*://*.bric75.com/*",
    "*://*.runthesims.com/*",
    "*://*.stripe.com/*",
    "*://*.execute-api.us-east-1.amazonaws.com/*",
    "unlimitedStorage",
    "identity"
  ]
}