Fixed in https://github.com/badbundle/vault-app/pull/605 (merged as 7408d0bf).
- Header: the export page opens with "Export Your Vault", explaining once what both options share: the whole vault, encrypted with your backup password.
- Grouped by purpose: the two big buttons are now titled rows with descriptions, in two sections. Keep a Backup holds PDF Backup; Move to Another Device holds Transfer with QR Codes. Each section has a footer explaining when and how to use it.
- Behaviour: unchanged, including authentication, the password check and both sheets.