It looks like this tool imports bank CSV. You can produce similar CSV with hledger's register command (or aregister, in master). Export one account and one currency at a time. Eg:

    $ hledger -f examples/sample.journal reg checking cur:'\$' -O csv
    "txnidx","date","code","description","account","amount","total"
    "1","2008-01-01","","income","assets:bank:checking","$1","$1"
    "2","2008-06-01","","gift","assets:bank:checking","$1","$2"
    "3","2008-06-02","","save","assets:bank:checking","$-1","$1"
    "5","2008-12-31","","pay off","assets:bank:checking","$-1","0"

I don’t know about hledger but getting out of ledger to YNAB was a royal PITA. Partly because ledger is so flexible because it is based on pure unadulterated double entry accounting, so its csv export is based on an entry per line rather than per transaction and that’s useless for most imports as they assume it’s a one transaction per line and you do splits once imported