Unfortunately, the page doesn't include a list of the items that are synced. If you don't use Chrome, you can't access your bookmarks from an online interface and that's pretty strange.
Google Dashboard shows even more information about Chrome Sync: autofill profiles, app settings, search engines and the date of the last sync.
If you're curious to find technical information about Chrome Sync internals, open a new tab in Chrome, paste this: chrome://sync-internals/ and press Enter. You'll find that Chrome synchronizes a lot more things: app notifications, device information, dictionaries, experiments, extension settings, favicons.