Duplicate URL with “/embed/” at the end?

Hi,

I was checking Google’s index of my site and noticed a duplicate page, that’s just a blog post with “/embed/” added to the end of the URL.

Like this:

website.com/blog-post-url/embed/

It loads a page that appears identical to the normal URL:

website.com/blog-post-url/

Does anyone know what might have added this extra URL to my site, with the /embed/ at the end? I just don’t know where to even begin figuring it out.