Examine source code of Notion Mate

{
  "name": "Notion Mate",
  "version": "2.5.2",
  "description": "Notion Mate productivity with 30+ customizations like outline TOC, small text, mark manager, image viewer, scroll to top, theme etc.",
  "action": {
    "default_title": "Click to view feature",
    "default_popup": "popup.html"
  },
  "manifest_version": 3,
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "activeTab",
    "fontSettings"
  ],
  "icons": {
    "16": "images/16.png",
    "32": "images/32.png",
    "48": "images/48.png",
    "64": "images/64.png",
    "128": "images/128.png",
    "256": "images/256.png",
    "512": "images/512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.notion.so/*",
        "*://*.notion.site/*",
        "*://*.notion.com/*",
        "https://extensionpay.com/*"
      ],
      "css": [],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "homepage_url": "http://www.notionmate.top",
  "browser_specific_settings": {
    "gecko": {
      "id": "{979873A7-E19D-A819-FF52-823B290CBAFA}"
    }
  }
}