For nm.debian.org, at 2021-03-25: I have worked with Jakub Ružička since early November 2020 on lua-binaryheap (#974080), knot and knot-resolver. For this past work, Jakub Ružička sent mails using the email address jakub.ruzicka@nic.cz which is the one he is using on nm.debian.org, and Jakub signed his work and email using a GPG key with fingerprint 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C. Jakub has also signed several commits (most of his commits, I think) in the repositories of the above mentioned packages using his key. E.g.: https://salsa.debian.org/jruzicka/lua-binaryheap/-/commit/d4fa1e41c3e35b63bc1d80d2ce5ded5306cbaade https://salsa.debian.org/dns-team/knot-dns/-/commit/81517b939c0d4539732ef426358d44ba25aa3f2f https://salsa.debian.org/dns-team/knot-resolver/-/commit/f92519d8b5baae5e1038af445435880c8ef00af8 I've made sure that Jakub is able to decrypt encrypted messages sent to this key and that he is able to sign messages with the same key. Due to the interactions we had since November 2020, I'm convinced that Jakub Ružička, as his present himself on nm.debian.org, is the rightful owner of both email jakub.ruzicka@nic.cz and GPG key 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C.
For nm.debian.org, on 2021-04-06: Since late 2020, I have worked with Jakub Ružička reviewing changes to several Debian packages, including knot and knot-resolver. For this past work, Jakub Ružička sent mails using the email address jakub.ruzicka@nic.cz which is the one they're using on nm.debian.org, and they signed their work and email using a GPG key with fingerprint 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C. Due to the long-term interactions we had, I'm convinced that Jakub Ružička as they present themselves on nm.debian.org is the rightful owner of both email jakub.ruzicka@nic.cz and GPG key 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C.
For nm.debian.org, at 2022-09-12: I have worked with Jakub Ružička since early November 2020 on lua-binaryheap (#974080), knot, knot-resolver among other packages. For this past work, Jakub Ružička sent mails using the email address jakub.ruzicka@nic.cz which is the one he is using on nm.debian.org, and Jakub signed his work and email using a GPG key with fingerprint 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C. Jakub also uses to sign his git commits/tags in the repositories of the above mentioned packages, using his key. E.g.: https://salsa.debian.org/jruzicka/lua-binaryheap/-/commit/d4fa1e41c3e35b63bc1d80d2ce5ded5306cbaade https://salsa.debian.org/dns-team/knot-dns/-/commit/81517b939c0d4539732ef426358d44ba25aa3f2f https://salsa.debian.org/dns-team/knot-resolver/-/commit/f92519d8b5baae5e1038af445435880c8ef00af8 and more recently: https://salsa.debian.org/dns-team/knot-dns/-/tree/debian/3.2.0-3 I've made sure that Jakub is able to decrypt encrypted messages sent to this key and that he is able to sign messages with the same key. This public mail (from 26 Aug 2021) has also been signed by Jakub: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=991463#35 Due to the interactions we had since November 2020, I'm convinced that Jakub Ružička, as his present himself on nm.debian.org, is the rightful owner of both email jakub.ruzicka@nic.cz and GPG key 23EB CF7E 8FC4 7556 7871 00DF A425 4072 E373 042C.