I'm not sure if the credential lists that HIBP pulls from always have the associated service/site. Looking up one of my emails, there's a mix of data breaches of specific sites (which are shown) and big lists of credentials, like the one in this blog post. The latter don't always have the associated source; the Pemiblanc list doesn't include the source, which is explicitly talked about in the associated blog post [1]. It'd be nice to display the source when possible, though.

[1] https://www.troyhunt.com/the-111-million-pemiblanc-credentia...