I have no affiliation with Bitwarden (other than being a customer), so I don’t have any ability to modify the official Help docs. However, there is a link at the bottom of each page in the Help Center, which you can click to “Make a suggestion to this article”; you could try submitting a suggestion there.
There is a (now somewhat outdated) backup guide written by a former community member (David H), which you can find under the tag tips:backups. A brief description of the data.json-based approach to vault backups is described in the top comment in the discussion of David H’s backup guide.