I have written a userspace hook to intercept all code changes in the Observable Runtime, which allows point-in-time recovery by rewriting the cells to be the same as in the past. Furthermore, its a building block towards serializing and replaying the history from IndexDB, so you don't lose changes if you refresh and/or forget to export to file. Its cool that can be done from userspace, a year ago I felt history might be a challenge, but no!