Your auto bid is private which means only we can see it (you can also see it and keep track of your current auto bids). 

Other bidders and the seller can’t see your auto bid limit or even that you’ve set an auto bid.

When an individual bid is placed, all bidders can see it in the bid history section of the lot page. 

However, they can’t see whether an individual bid is a regular bid or part of an auto bid.