Learn English – Usage of phrase “revert back”

Yes and no.

Reading around on the internet, it seems that this was originally just an error (and still is one for most native English speakers), but in some non-native-speaker speech communities it has become established as a common usage. From Paul Brians’ Common Errors in English Usage

The most common meaning of “revert” is “to return to an earlier condition, time, or subject.” When Dr. Jekyll drank the potion he reverted to the brutish behavior of Mr. Hyde. But in South Asia it has become common to use “revert” instead of “reply,” writing when people want you to get back to them about something: “revert to me at this address.” In standard English this would literally mean they are asking you to become them, so it is best to stick with “reply” when dealing with non-South Asian correspondents. Even some South Asians disapprove of this use of “revert.”

Googling eg "please revert to me" or "I will revert to you" (and skipping past the first few pages of results, which are mostly usage/grammar sites) gives lots of examples in this usage in the wild. Interestingly, it doesn’t seem to function as an exact synonym for ‘reply’; hardly anybody writes eg “revert to this letter”.

If archiving a piece of data changes its status with respect to the main module of your program, then restoring will put things back the way they were.