Kleopatra from version 3.0 on supports OpenPGP Smartcards. Currently it does not support the URL data field on a smartcard.
This can be useful if a smartcard is used for the first time on an installation, as it enables the corresponding public key to be fetched from the given URL.
GPA already supports this, Kleopatra should support fetching and changing the URL, too.
Last commit of the series: https://commits.kde.org/kleopatra/c5567d6915bb0e76284281590282d942966322b0
The behavior differs from GPA in that Kleopatra does not directly import the URL but instead opens it through Destktop Services.
This is because users may have landing pages that are not directly the importable PGP Key and if the URL target is application/pgp-keys the target should be opened by desktop services with Kleopatra anyway. This would directly trigger the import.