Examine source code of NG Music Stats

{
  "manifest_version": 3,
  "name": "NG Music Stats",
  "version": "0.7.8",
  "browser_specific_settings": {
    "gecko": {
      "id": "ngmusicstats@eqy",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "description": "Track and compare Newgrounds audio stats directly on the site.",
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "96": "icon96.png",
    "128": "icon128.png",
    "256": "icon256.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "icon16.png",
        "icon32.png",
        "icon48.png",
        "icon128.png",
        "ngmsh_default_bg.png"
      ],
      "matches": [
        "https://*.newgrounds.com/*",
        "https://newgrounds.com/*"
      ]
    }
  ],
  "action": {
    "default_title": "NG Music Stats",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "https://*.newgrounds.com/*",
    "https://newgrounds.com/*",
    "https://*.ngfiles.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://*.newgrounds.com/*",
        "https://newgrounds.com/*"
      ],
      "js": [
        "ext.js",
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_idle"
    }
  ]
}