Examine source code of Toolkit for YNAB

{
  "manifest_version": 2,
  "author": "Toolkit for YNAB",
  "name": "Toolkit for YNAB",
  "description": "UI customizations and tweaks for the web version of YNAB.",
  "version": "3.20.0",
  "content_scripts": [
    {
      "matches": [
        "http://*.youneedabudget.com/*",
        "https://*.youneedabudget.com/*",
        "https://*.ynab.com/*",
        "http://*.ynab.com/*"
      ],
      "all_frames": true,
      "run_at": "document_idle",
      "js": [
        "content-scripts/extension-bridge.js"
      ]
    },
    {
      "matches": [
        "http://*.youneedabudget.com/*",
        "https://*.youneedabudget.com/*",
        "https://*.ynab.com/*",
        "http://*.ynab.com/*"
      ],
      "all_frames": true,
      "run_at": "document_start",
      "js": [
        "content-scripts/enable-ember-debug.js"
      ]
    }
  ],
  "icons": {
    "16": "assets/images/icons/button.png",
    "32": "assets/images/icons/icon32.png",
    "48": "assets/images/icons/icon48.png",
    "64": "assets/images/icons/icon64.png",
    "100": "assets/images/icons/icon100.png",
    "128": "assets/images/icons/icon128.png",
    "256": "assets/images/icons/icon256.png",
    "512": "assets/images/icons/icon512.png",
    "1024": "assets/images/icons/icon1024.png"
  },
  "web_accessible_resources": [
    "assets/*",
    "web-accessibles/*"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "homepage_url": "https://github.com/toolkit-for-ynab/toolkit-for-ynab/",
  "options_ui": {
    "open_in_tab": true,
    "page": "options/index.html"
  },
  "permissions": [
    "http://*.youneedabudget.com/*",
    "https://*.youneedabudget.com/*",
    "https://*.ynab.com/*",
    "http://*.ynab.com/*",
    "storage"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_action": {
    "default_icon": "assets/images/icons/button.png",
    "default_title": "Toolkit for YNAB",
    "default_popup": "popup/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4F1FB113-D7D8-40AE-A5BA-9300EAEA0F51}"
    }
  }
}