Example of mini site links,
One-line sitelinks-mini sitelinks-Explain tips but dont confused there you can see site links too. but site links apear most time when you search using brand or a web site name etc
They are totally show by search engines using site maps and site structure and most valuable pages indexed that seen by search engines.
here this article show how mini site links index by google
You can here learn how mini site links get indexed and why there are started mostly by google after 2009 dot com boom,,now most websites with good structure and content get this site link featured added when someone do the search by key words.
Few More content Resources links here,