% APNIC found the following authoritative answer from: whois.ripe.net

% This is the RIPE Database query service.
% The objects are in RPSL format.
%
% The RIPE Database is subject to Terms and Conditions.
% See https://apps.db.ripe.net/docs/HTML-Terms-And-Conditions

% Note: this output has been filtered.
%       To receive output for a database update, use the "-B" flag.

% Information related to '2001:638:501::/48'

% Abuse contact for '2001:638:501::/48' is 'abuse@dfn.de'

inet6num:       2001:638:501::/48
netname:        UNI-ESSEN
descr:          Universitaet Duisburg-Essen
descr:          Zentrum fuer Informations- und Mediendienste
descr:          Schuetzenbahn 70
descr:          45127 Essen
descr:          Germany
country:        DE
admin-c:        GK6979-RIPE
tech-c:         MK26491-RIPE
mnt-by:         DFN-HM-MNT
mnt-irt:        IRT-DFN-CERT
status:         ASSIGNED
created:        2002-08-06T16:15:33Z
last-modified:  2024-07-02T15:21:37Z
source:         RIPE # Filtered

person:         Guido Kerkewitz
address:        Universitaet Duisburg-Essen
address:        Zentrum fuer Informations- und Mediendienste
address:        Forsthausweg 2
address:        47057 Duisburg
address:        Germany
phone:          +49 203 379 4253
nic-hdl:        GK6979-RIPE
mnt-by:         DFN-NTFY
created:        2021-12-07T09:22:28Z
last-modified:  2021-12-07T09:22:28Z
source:         RIPE

person:         Martin Klick
address:        Universitaet Duisburg-Essen
address:        Zentrum fuer Informations- und Mediendienste
address:        Schuetzenbahn 70
address:        45127 Essen
address:        Germany
phone:          +49 201 183 3973
nic-hdl:        MK26491-RIPE
mnt-by:         DFN-NTFY
created:        2024-07-02T14:58:48Z
last-modified:  2024-07-02T14:58:48Z
source:         RIPE # Filtered

% Information related to '2001:638::/32AS680'

route6:         2001:638::/32
descr:          DFN-V6-AGG1
origin:         AS680
mnt-by:         DFN-MNT
mnt-routes:     ESANIC-MNT { 2001:638:30d::/48 }
created:        2005-06-23T15:23:59Z
last-modified:  2014-12-11T12:25:57Z
source:         RIPE

% This query was served by the RIPE Database Query Service version 1.113.2 (DEXTER)

Search for
IP address lookups			Miscellaneous queries
-l	1st level less specific		-i	Inverse attributes	None admin-c admin-c,tech-c,zone-c author cross-mnt cross-nfy local-as mbrs-by-ref member-of mnt-by mnt-lower mnt-nfy mnt-routes notify nserver origin person referral-by rev-srv sub-dom tech-c upd-to zone-c
-L	All less specific		-T	Object types	All as-block as-set aut-num domain filter-set inet-rtr inet6num inetnum irt key-cert mntner peering-set person role route route-set rtr-set
-m	1st level more specific
-M	All more specific		Query hints Include "AS" in front of an AS number. Example: AS4808 Include "-t" (template only) or "-v" (template and description) in front of an object name to view the template Example: -t inetnum
-x	Exact match only
-d	Associated reverse domain