Examine source code of Tab Icon Badge

{
  "manifest_version": 2,
  "name": "Tab Icon Badge",
  "description": "Overlays a badge on the tab icon with the unread count extracted from the number in the title's parentheses.",
  "version": "1.0.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "tab_icon_badge@noclip.dev"
    }
  },
  "icons": {
    "32": "icons/icon.svg",
    "64": "icons/icon.svg",
    "128": "icons/icon.svg",
    "256": "icons/icon.svg"
  },
  "permissions": [
    "http://*/*",
    "https://*/*",
    "storage",
    "sessions",
    "tabs"
  ],
  "background": {
    "page": "background/background.html"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": false,
    "open_in_tab": false
  }
}