This repo is about converting Workflowy JSON to OPML, and perhaps in different directions. Though, the primary purpose of this repo is to provide very easy tooling to convert a Workflowy .backup file to OPML, which you can just paste into Workflowy itself.
This, in contrary to, Workflowy .backup files, which cannot be pasted, and you need to import the entire file, probably overwriting everything in your account, as it can take up a certain amount of time to import.