Examine source code of Canvas Refined

{
  "manifest_version": 3,
  "name": "CanvasRefined",
  "description": "Even More Feature packed extension for Canvas.",
  "version": "6.2.61",
  "icons": {
    "16": "icon/icon-16.png",
    "32": "icon/icon-32.png",
    "48": "icon/icon-48.png",
    "128": "icon/icon-128.png"
  },
  "action": {
    "default_icon": {
      "19": "icon/icon-19.png",
      "38": "icon/icon-38.png"
    },
    "default_popup": "html/popup.html",
    "default_title": "Canvas Refined"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "service_worker": "js/background.js"
  },
  "options_page": "html/options.html",
  "content_scripts": [
    {
      "matches": [
        "https://*/*"
      ],
      "js": [
        "css/darkmodecss.js",
        "js/content.js"
      ],
      "css": [
        "css/content.css"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "storage"
  ],
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "canvasrefined@guysan.site",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}