Examine source code of Kumify

{
  "_comment": "this is p much the base stuff",
  "manifest_version": 3,
  "name": "Kumify",
  "version": "2.1.0",
  "icons": {
    "128": "assets/icon/IconKumiko.png"
  },
  "description": "Make every YouTube Thumbnail into Kumiko!",
  "host_permissions": [
    "https://www.youtube.com/*"
  ],
  "permissions": [
    "storage"
  ],
  "_comment1": "when it sees you on youtube.com(and its finished loading from document_idle), itll run main.js",
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "main.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "_comment2": "lets websites access these within the extension. in this case, ANY(matches) can access ANY(*) file in images that is a png",
  "web_accessible_resources": [
    {
      "resources": [
        "assets/images/*.PNG",
        "assets/images/*.gif",
        "assets/popup/*.jpeg",
        "assets/popup/*.webp",
        "assets/popup/*.png",
        "assets/popup/*.gif",
        "assets/gifs/*.gif"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "_comment3": "this is the button on the browser toolbar",
  "action": {
    "default_popup": "popup.html"
  },
  "_comment4": "FIREFOX STUFF AYDGBCUASDFUYTXAFVSDYX",
  "browser_specific_settings": {
    "gecko": {
      "id": "Kumify@Denzmar.com",
      "strict_min_version": "109.0"
    }
  }
}