Google Cache Browser is an experimental project designed to improve the usability of Google's search engine cache.
There is one simple and popular way to see the version of a web page in Google's cache - send a search query cache:http://example.com/. Then, of course, if the page is indexed, it will take you to Google's copy of http://example.com/. The only problem is that clicking on any link will lead you to a non-cached version of the page which you won't be able to browse. Of course, if you really need it, you can copy page address and send request again but this is so excruciatingly inconvenient. It's easier to just forget about it.
Some time ago, about three or four years ago, I already puzzled over this problem. As a result Google Cache Browser was born that allowed to bypass the pages from Google's cache and transform them in such a way that they go through Google Cache Browser again and in this way it became convenient to browse cached sites. But rather quickly its problems showed up: the server IP was constantly getting banned by Google and a lot of traffic was being consumed on my hosting plan. Therefore, the service waffled and waffled, and died about a year ago.