If you recently tried adding a new linux source repository in Ubuntu 22.04, then you might have seen this warning mesage: Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)). Apt-key is a sub-command of apt used to manage asymmetric encryption keys in order to authenticate packages. It was found some time ago to be vulnerable to man-in-the-middle attacks (see CVE-2011-3374). Now it has finally been deprecated and will be deleted at some point in the future.