Where does DVD Player remember all the DVDs its ever played?

When you put in a previously-played DVD, it will skip to a certain point (or ask if it should).

Where is this information stored? I found the answer here once a long time ago but despite trying several methods of searching, I can't locate it anymore. So here I am!

I used to watch a LOT of DVDs from the library and a year or two ago I deleted all the previously-viewed-DVD information and opened up a ton of space on my hard drive. Thanks!