This is a colour variant page for the Red Widget. Because it shares content with the main Product page, it declares that page as the canonical.
The canonical tag in the <head> of this page reads:
<link rel="canonical" href="https://robots-txt-lab.pages.dev/product">
This means Google should consolidate all ranking signals to /product.
But this URL (/product-red) was accidentally left in the sitemap — telling Google
to treat it as an independent page worth discovering.