Examine source code of Textmode Overlay

{
  "manifest_version": 3,
  "name": "Textmode Overlay",
  "description": "Turn <canvas> and <video> elements into live ASCII art.",
  "version": "1.2.0",
  "icons": {
    "16": "/icons/icon-16.png",
    "32": "/icons/icon-32.png",
    "48": "/icons/icon-48.png",
    "128": "/icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "scripting",
    "storage",
    "unlimitedStorage"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "fonts/UrsaFont.ttf",
        "fonts/atascii.ttf",
        "fonts/Bescii-Mono.ttf",
        "fonts/cpc464.ttf"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "action": {
    "default_title": "Textmode Overlay",
    "default_icon": {
      "16": "/icons/icon-16.png",
      "32": "/icons/icon-32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{61e3318b-fa4a-4c0c-883f-3723d22a3834}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "type": "module",
    "scripts": [
      "background.js"
    ]
  }
}