Many software provides their own APT repositories that have to be configured manually.

• Dealing with third party APT repositories in Ubuntu

Manual steps using Adoptium as example.

GPG key:

$ cd /tmp
$ curl -o gpg.key https://packages.adoptium.net/artifactory/api/gpg/key/public
$ file gpg.key
gpg.key: PGP public key block Public-Key (old)
$ cat gpg.key | gpg --dearmor > gpg.key.dearmored
gpg.key.dearmored: OpenPGP Public Key Version 4, Created Tue Nov 16 14:16:20 2021, RSA (Encrypt or Sign, 2048 bits); User ID; Signature; OpenPGP Certificate
$ sudo cp gpg.key.dearmored /etc/apt/keyrings/adoptium.gpg
$ sudo chmod a=r /etc/apt/keyrings/adoptium.gpg

APT repository configuration:

$ echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/adoptium.gpg] https://packages.adoptium.net/artifactory/deb $(awk -F= '/^VERSION_CODENAME/{print$2}' /etc/os-release) main" > adoptium.list
$ sudo cp adoptium.list /etc/apt/sources.list.d/
$ sudo chmod a=r /etc/apt/sources.list.d/adoptium.list

$ sudo apt update

Source: apt-repo.md Created: 2024-03-18T08:37:07+02:00 Changed: 2024-03-18T08:37:07+02:00