Examine source code of Get Joke Extension

{
  "name": "Get Joke Extension",
  "short_name": "Get Joke",
  "version": "1.13.0",
  "author": "MarkAlexI",
  "homepage_url": "https://ext.pp.ua/get-joke-extension.html",
  "manifest_version": 3,
  "icons": {
    "16": "images/icon-16.png",
    "32": "images/icon-32.png",
    "192": "images/icon-192.png"
  },
  "description": "Get Joke Extension is a simple web extension to get random jokes. Press the button for funny jokes to cheer you up! Get random mem: Programming, Pun, Dark, Spooky and Christmas.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d9b8e5c3-3c54-4f6a-bf91-6a4b80d8e978}"
    },
    "gecko_android": {
      "id": "{d9b8e5c3-3c54-4f6a-bf91-6a4b80d8e978}",
      "strict_min_version": "113.0"
    }
  },
  "permissions": [
    "storage",
    "webRequest"
  ],
  "action": {
    "default_popup": "index.html",
    "default_title": "Just joke"
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": false
  },
  "commands": {
    "refresh-joke-feature": {
      "suggested_key": {
        "default": "Ctrl+Shift+X",
        "linux": "Ctrl+Shift+J"
      },
      "description": "Send a 'refresh-joke-feature' event"
    }
  },
  "content_security_policy": {
    "extension_pages": "default-src 'self'; style-src 'self'; connect-src 'self' https://v2.jokeapi.dev"
  }
}