I don't know but I've been using this technique for a year or two now with great success. The Google authenticator just stores its secrets in the salute db every app gets.
Autocorrect kicked in there... sqlite* (it is absurdly difficult to put an asterisk at the end of a message on HN. it seems to require a trailing whitespace[1] for it to show up, however the input is trimmed, so...)
I have not, but I have extracted the backup with https://sourceforge.net/projects/adbextractor/ and inspected the contents, visually confirming the secrets are there. Even if a restore doesn't work, I can re-enter them manually from the information in the sqlite database. However I fully expect a restore to work.
