https://www.icloud.com/#settings currently shows an “Advanced” subsection for restoring Contacts. It provides options to restore an iCloud data set “archive” from iCloud (not to be confused with restoring an entire iOS device backup):
Notes aren’t on the list though. They have their own note-specific backup restore option, but it’s at the level of an individual note and there’s no version restore, only the ability to undo a delete for 30 days by restoring a Note from “recently deleted”. (BTW, if you Share a Note only the Owner can “delete” — but anyone with Edit privileges can remove all content — and since there’s no version undo that means anyone who can edit a Note can delete it without a recovery option.)
Sharing is another area of odd inconsistency. Notes must be shared one at time, but multiple Reminders can belong to a set of People.
I’d like to see Notes add Google-style Note-specific version save/restore and share by container (folder) as well as Note, but there’s no rumor of that in iOS 11. I’d pay for a third party solution for iCloud, similar to what CloudPull does for Google App docs, but I fear the demand is too small (for example). An Apple iCloud Drive folder view of Notes  would be a big help; I’d then be able to restore an individual Note from a Time Machine or Carbon Copy Cloner backup …
Anyone have an AppleScript to create a local daily snapshot of Notes? (There is this, but in Sierra Apple omitted AppleScript dictionary support for PDF creation).
The world moves in unexpected ways. We seem to be converging on a form of backup that’s a regression for people like me, but a big improvement for most. There’s probably some kind of futurist principle there — the good-enough mass solution will drive out the elite ideal …
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 The main reason I’m still on Simplenote is that nvAlt on my Mac maintains a synchronized file store that works just like this. Perfect data freedom — but almost nobody appreciates this …
 As of Sierra at least some parts of Notes are in /Users/[username]/Library/Group Containers/group.com.apple.notes. This location has changed a few times. Note content is distributed between media files (PDF, etc) and text in a sqlite database, so recreating an individual Note document as, say, an RTF file, is a non-trivial task. For example (sqlite browser):
I suppose Time Machine backups of this folder might be a kind of ‘restore all notes’ option, but restoring a version of an individual Note would be tricky…. (There’s something deep here about the ways in which we assemble bits to create something our brains perceive and our tools manipulate, but it’s beyond my ken. Once upon a time a BYTE article would have traced the roots of the Notes sqlite store back to database file systems of the 1980s…)