With a NetKey-v15 test card (Signature Card V2.0) which contains S/MIME certificates with brainpool curves, loading of the certificates in the smart card view after clicking the button "load certificates" does not succeed. No certificates are shown and the button remains greyed out.
Debugview
[9440] org.kde.pim.kleopatra: Card 89490171500022806460 info: [9440] org.kde.pim.kleopatra: READER : SCM Microsystems Inc. SPRx32 USB Smart Card Reader 0 [9440] org.kde.pim.kleopatra: SERIALNO : 89490171500022806460 [9440] org.kde.pim.kleopatra: APPTYPE : nks [9440] org.kde.pim.kleopatra: APPVERSION : F [9440] org.kde.pim.kleopatra: CHV-STATUS : 3 3 -4 0 [9440] org.kde.pim.kleopatra: KEYPAIRINFO : 4FE905D9AF633D134BB74109526CC762EC9BC8DC NKS-NKS3.4531 sa - brainpoolP256r1 [9440] org.kde.pim.kleopatra: CERTINFO : 101 NKS-NKS3.C000 [9440] org.kde.pim.kleopatra: KEYPAIRINFO : 9807C934B87DCAB103D5E8A4D69C3CFB600F75DA NKS-NKS3.45B1 e - brainpoolP256r1 [9440] org.kde.pim.kleopatra: CERTINFO : 101 NKS-NKS3.C200 [9440] org.kde.pim.kleopatra: CERTINFO : 111 NKS-NKS3.C20E [9440] org.kde.pim.kleopatra: CERTINFO : 101 NKS-NKS3.C208 [9440] org.kde.pim.kleopatra: KEYPAIRINFO : 811564E41DF97BB799FF058E407CC88569BB7EEC NKS-NKS3.4571 a - brainpoolP256r1 [9440] org.kde.pim.kleopatra: CERTINFO : 101 NKS-NKS3.C500 [9440] org.kde.pim.kleopatra: KEYPAIRINFO : FFEFC219B3698D26B46A376533EB91ADD4609C8C NKS-ESIGN.4531 s - brainpoolP256r1 [9440] org.kde.pim.kleopatra: CERTINFO : 101 NKS-ESIGN.C000 [9440] org.kde.pim.kleopatra: CERTINFO : 100 NKS-ESIGN.C001 [9440] org.kde.pim.kleopatra: CERTINFO : 111 NKS-ESIGN.C00E [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: pattern= &4FE905D9AF633D134BB74109526CC762EC9BC8DC [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: e= 0 ; key.isNull() false [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: pattern= &9807C934B87DCAB103D5E8A4D69C3CFB600F75DA [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: e= 0 ; key.isNull() false [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: pattern= &811564E41DF97BB799FF058E407CC88569BB7EEC [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: e= 16383 ; key.isNull() true [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: pattern= &FFEFC219B3698D26B46A376533EB91ADD4609C8C [9440] org.kde.pim.kleopatra: parse_keypairinfo_and_lookup_key: e= 0 ; key.isNull() false [9440] org.kde.pim.libkleo: sendCommand "READKEY --card --no-data -- NKS-NKS3.4531" [9440] org.kde.pim.libkleo: sendStatusLinesCommand "READKEY --card --no-data -- NKS-NKS3.4531" : got ( ) [9440] org.kde.pim.libkleo: sendCommand "READKEY --card --no-data -- NKS-NKS3.45B1" [9440] org.kde.pim.libkleo: "C:/Users/g10code.WIN-TEST3/AppData/Roaming/gnupg/private-keys-v1.d/4FE905D9AF633D134BB74109526CC762EC9BC8DC.key" [9440] org.kde.pim.libkleo: "C:/Users/g10code.WIN-TEST3/AppData/Roaming/gnupg/private-keys-v1.d/9807C934B87DCAB103D5E8A4D69C3CFB600F75DA.key" [9440] org.kde.pim.libkleo: sendStatusLinesCommand "READKEY --card --no-data -- NKS-NKS3.45B1" : got ( ) [9440] org.kde.pim.libkleo: sendCommand "READKEY --card --no-data -- NKS-NKS3.4571" [9440] org.kde.pim.libkleo: "C:/Users/g10code.WIN-TEST3/AppData/Roaming/gnupg/private-keys-v1.d/811564E41DF97BB799FF058E407CC88569BB7EEC.key" [9440] org.kde.pim.libkleo: sendStatusLinesCommand "READKEY --card --no-data -- NKS-NKS3.4571" : got ( ) [9440] org.kde.pim.libkleo: sendCommand "READKEY --card --no-data -- NKS-ESIGN.4531" [9440] org.kde.pim.libkleo: sendStatusLinesCommand "READKEY --card --no-data -- NKS-ESIGN.4531" : got ( ) [9440] org.kde.pim.kleopatra: ReaderStatusThread[2nd]: waiting for commands [9440] org.kde.pim.libkleo: "C:/Users/g10code.WIN-TEST3/AppData/Roaming/gnupg/private-keys-v1.d/FFEFC219B3698D26B46A376533EB91ADD4609C8C.key"