Thanks. I expect it is just a typo in the few cases that there are. I suppose some editors could mean an unimproved surface, which is a bit more specific than unpaved, but it's unclear and like an oxymoron. If this was the meaning I would prefer 'natural', and would still think it reasonable for StreetComplete to ask for a more specific tag if possible, as with unpaved. As a side issue, I would sometimes like to tag paths as stony ground, which I don't think is really covered by the other options except unpaved, but it's very rarely used currently.