Ask HN: How do you find out when someone links to your blog?

I don't have analytics built into my site at all, but I can see whatever CPanel has which is usually Webalyzer or AWStats.

Back when Google wasn't trying to stop people from visiting sites related to their searches, they used to have a link: operator that would give you that information. Apparently they got rid of that functionality back in 2017.

You can look at back links in marginalia site data.