GPG4win claims to follow the recommendations of the BSI but is there an official qualification by the BSI (or another European information security agency) for the protection provided by GPB4win and up to which level ?
yes, the latest “approval” is BSI-VSA-10503 for GnuPG VS Desktop
(which is a quality guaranteed GnuPG-Desktop distribution will all Gpg4win components),
you’ll get more infos from https://gnupg.com/index.html.
Its for handling EU RESTRICTED (VS-NfD), and (citing from GnuPG.com):
"For EU CONFIDENTIAL (VS-V) data the German Federal Institution for Information Security (BSI) can approve the use of GnuPG on an individual basis. "
Thanks Bernhard for this useful answer