Examine source code of Epupp: Live Tamper your Web

{
  "description": "Make web pages you visit behave like you want them to with live tampering, or with userscripts, TamperMonkey style.",
  "host_permissions": [
    "<all_urls>"
  ],
  "permissions": [
    "scripting",
    "activeTab",
    "storage",
    "webNavigation",
    "alarms"
  ],
  "name": "Epupp: Live Tamper your Web",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; connect-src 'self' ws://localhost:* ws://127.0.0.1:*;"
  },
  "devtools_page": "devtools.html",
  "browser_specific_settings": {
    "gecko": {
      "id": "browser-jack-in@example.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-disconnected-16.png",
      "32": "icons/icon-disconnected-32.png",
      "48": "icons/icon-disconnected-48.png",
      "128": "icons/icon-disconnected-128.png"
    }
  },
  "manifest_version": 3,
  "version": "0.0.20",
  "web_accessible_resources": [
    {
      "resources": [
        "icons/icon.svg",
        "vendor/scittle.js",
        "vendor/scittle.nrepl.js",
        "vendor/scittle.pprint.js",
        "vendor/scittle.promesa.js",
        "vendor/scittle.replicant.js",
        "vendor/scittle.js-interop.js",
        "vendor/scittle.reagent.js",
        "vendor/scittle.re-frame.js",
        "vendor/scittle.cljs-ajax.js",
        "vendor/react.production.min.js",
        "vendor/react-dom.production.min.js",
        "ws-bridge.js",
        "trigger-scittle.js",
        "disable-scittle-auto-eval.js",
        "userscripts/epupp/*.css"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}