Examine source code of TabTailor

{
  "manifest_version": 3,
  "name": "TabTailor",
  "description": "Easily customize your new tab background with videos, GIFs, or images",
  "version": "0.2.0",
  "action": {
    "default_popup": "index.html"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "icons": {
    "16": "src/assets/16.png",
    "32": "src/assets/32.png",
    "48": "src/assets/48.png",
    "128": "src/assets/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-tailor@rxliuli.com"
    }
  }
}