Back in April, Google introduced breadcrumb URL markup for the search results. It would show a breadcrumb trail in the mobile and maybe desktop Google snippet instead of just your URL. This also was introduced with the Site Name markup.
Google's Gary Illyes announced on Google+ that Google has fresh new technical documentation on the breadcrumb schema for you all. He said "The new Breadcrumbs documentation is now live on Google Developers! Check it out and make use of it!"
The new docs are over at developers.google.com/structured-data/breadcrumbs.
I should note, that Gary also added on Twitter after being asked, that the breadcrumb hyperlinks that dropped out last year are not likely returning. Gary said he isn't aware of any plans to bring back that feature.
@DeanCruddace I'm not aware of such plans.— Gary Illyes (@methode) June 15, 2015
The feature was removed when there were exploits that let webmasters inject stuff into those links and fake it.
Forum discussion at Google+.