In GnuPG VS-Desktop we have the text "VS-NfD compliant" (green) or "not VS-NfD compliant" (red) in the right corner of the status line in the main Kleopatra window. This indicates whether GnuPG VS-Desktop is installed in compliance with classified information requirements or not.

This is explained in the handbook which was compiled for the approval by the BSI.

This should be shortly explained in a tooltip.

Text proposal ("VS-NfD Compliant" is a variable, "EU Restricted", "NATO Restricted" are also possible)
"This installation is VS-NfD Compliant." / "Diese Installation ist VS-NfD-konform."
or longer:
"This installation is VS-NfD Compliant and can be used for VS-NfD Compliant data." / "Diese Installation ist VS-NfD-konform und darf für VS-NfD-konforme Daten verwendet werden."
("VS-NfD Compliant" is a variable)

Negative variety:
"This installation is NOT VS-NfD Compliant. Do *not* use for VS-NfD Compliant data." / "Diese Installation ist NICHT VS-NfD-konform. *Nicht* für VS-NfD-konforme Daten verwenden!"