Thanks for detecting that mistake and reporting it. I’ve submitted a fix to the blog post to use the same key installation instructions as are used in the Linux install guides.
The install guide instructions to install the GPG public key on Debian and Ubuntu are:
$ curl -fsSL https://pkg.jenkins.io/debian/jenkins.io-2023.key | sudo tee \
/usr/share/keyrings/jenkins-keyring.asc > /dev/null
$ echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \
https://pkg.jenkins.io/debian binary/ | sudo tee \
/etc/apt/sources.list.d/jenkins.list > /dev/null
The instructions for key installation on Red Hat / CentOS / Alma / Rocky are:
$ sudo rpm --import https://pkg.jenkins.io/redhat/jenkins.io-2023.key