This is a nice new feature. Now you can play around with your contacts, and if turns out you do not like what you end up with you can undo it all.
"There are many times in life when a do-over can come in handy. Perhaps you clicked “Send” on an email that was better left unsaid, or “Delete” on a contact before realizing you still needed it. Just like Gmail lets you unsend a message, you can now have a second chance with your contacts too.
We’ve added a new feature to Google Contacts that allows you to revert your contact list and undo any mistakes made up to 30 days in the past. Let’s say you accidentally deleted a bunch of contacts or wiped the contact data from your Gmail account by mistake while syncing to another device. Visit Gmail’s Contacts section, select “Restore contacts” in the “More actions” menu, and choose the time you would like to revert to."