Internal backlinks

[Mikey85]

When I check the backlinks of some sites, google shows a lot of links of the site I checked.

How is that possible?
How is it possible to create internal backlinks?

[PatrickDeese]

Google doesn't show all the backlinks for a domain, ever.

If your pages link to the home page, and they are indexed by google, they are counted as backlinks, even if you can't see them in a link:example.com command.