The GPG key has simply expired, as of 2021-03-20:
$ wget -q http://ddebs.ubuntu.com/dists/focal-proposed/Release http://ddebs.ubuntu.com/dists/focal-proposed/Release.gpg
$ gpg --verify Release.gpg Release gpg: Signature made Fri 19 Mar 2021 04:52:53 AM CET gpg: using RSA key 0xC8CAB6595FDFF622 gpg: Good signature from "Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <email address hidden>" [expired] gpg: Note: This key has expired! Primary key fingerprint: F2ED C64D C5AE E1F6 B9C6 21F0 C8CA B659 5FDF F622
$ gpg --list-key 0xC8CAB6595FDFF622 pub rsa4096/0xC8CAB6595FDFF622 2016-03-21 [SC] [expired: 2021-03-20] Key fingerprint = F2ED C64D C5AE E1F6 B9C6 21F0 C8CA B659 5FDF F622 uid [ expired] Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <email address hidden>
Time to generate a new key and distribute it, I guess. :-)
The GPG key has simply expired, as of 2021-03-20:
$ wget -q http:// ddebs.ubuntu. com/dists/ focal-proposed/ Release http:// ddebs.ubuntu. com/dists/ focal-proposed/ Release. gpg
$ gpg --verify Release.gpg Release
gpg: Signature made Fri 19 Mar 2021 04:52:53 AM CET
gpg: using RSA key 0xC8CAB6595FDFF622
gpg: Good signature from "Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <email address hidden>" [expired]
gpg: Note: This key has expired!
Primary key fingerprint: F2ED C64D C5AE E1F6 B9C6 21F0 C8CA B659 5FDF F622
$ gpg --list-key 0xC8CAB6595FDFF622 0xC8CAB6595FDFF 622 2016-03-21 [SC] [expired: 2021-03-20]
pub rsa4096/
Key fingerprint = F2ED C64D C5AE E1F6 B9C6 21F0 C8CA B659 5FDF F622
uid [ expired] Ubuntu Debug Symbol Archive Automatic Signing Key (2016) <email address hidden>
Time to generate a new key and distribute it, I guess. :-)