Examine source code of Minecraft 2d

{
  "manifest_version": 2,
  "name": "Minecraft 2d",
  "version": "2021.7",
  "description": "Minecraft in 2d. Play Minecraft in your Browser",
  "icons": {
    "48": "favicon.ico"
  },
  "options_ui": {
    "page": "index.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "48": "favicon.ico"
    },
    "default_title": "Minecraft 2d",
    "default_popup": "index.html"
  }
}