[Jammy]: puppet-agent has no installation candidate despite following instructions

Goal: have Puppet 6 agent on a ubuntu:jammy docker container to test Puppet scripts.

I have added Puppetlabs repositories, ran apt-get update and apt-get upgrade but still apt-get install puppet-agent fails with error 'has no installation candidate`.

Instructions I followed: Puppet instructions

What am I doing wrong?

Instructions of how to reproduce

Dockerfile

FROM ubuntu:jammy

EXPOSE 80

RUN apt-get update
RUN apt-get upgrade -y
RUN yes| unminimize
RUN apt-get install apt-utils -y

# packages we need
RUN apt-get install unzip -y
RUN apt-get install wget -y
RUN apt-get install puppet -y

Commands on the Docker container terminal

root@6d2e2ea018b6:/# history 
    1  wget https://apt.puppet.com/puppet6-release-jammy.deb
    2  dpkg -i puppet6-release-jammy.deb 
    3  apt-get update -y
    4  apt-get upgrade -y
    5  apt-get install puppet-agent

Command output

root@6d2e2ea018b6:/# wget https://apt.puppet.com/puppet6-release-jammy.deb
--2023-06-07 11:59:24--  https://apt.puppet.com/puppet6-release-jammy.deb
Resolving apt.puppet.com (apt.puppet.com)... 52.222.139.62, 52.222.139.78, 52.222.139.20, ...
Connecting to apt.puppet.com (apt.puppet.com)|52.222.139.62|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 11702 (11K) [application/x-debian-package]
Saving to: 'puppet6-release-jammy.deb'

puppet6-release-jammy.deb                       100%[=====================================================================================================>]  11.43K  --.-KB/s    in 0s      

2023-06-07 11:59:24 (127 MB/s) - 'puppet6-release-jammy.deb' saved [11702/11702]

root@6d2e2ea018b6:/# dpkg -i puppet6-release-jammy.deb 
Selecting previously unselected package puppet6-release.
(Reading database ... 10920 files and directories currently installed.)
Preparing to unpack puppet6-release-jammy.deb ...
Unpacking puppet6-release (6.0.0-23jammy) ...
Setting up puppet6-release (6.0.0-23jammy) ...
root@6d2e2ea018b6:/# apt-get update -y
Hit:1 http://ports.ubuntu.com/ubuntu-ports jammy InRelease
Get:2 http://ports.ubuntu.com/ubuntu-ports jammy-updates InRelease [119 kB]
Get:3 http://ports.ubuntu.com/ubuntu-ports jammy-backports InRelease [108 kB]
Get:4 http://ports.ubuntu.com/ubuntu-ports jammy-security InRelease [110 kB]
Get:5 http://apt.puppetlabs.com jammy InRelease [113 kB]
Get:6 http://apt.puppetlabs.com jammy/puppet6 all Packages [1316 B]
Get:7 http://apt.puppetlabs.com jammy/puppet6 arm64 Packages [1316 B]
Fetched 452 kB in 1s (417 kB/s)    
Reading package lists... Done
root@6d2e2ea018b6:/# apt-get upgrade -y
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@6d2e2ea018b6:/# apt-get install puppet-agent
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package puppet-agent is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'puppet-agent' has no installation candidate

What is going wrong?

Possibly important detail: I'm working on a M1 Macbook Pro.

puppet6-release-jammy.deb does not contain puppet-agent but requires it.

So download and install puppet-agent from where you got puppet6-release-jammy.deb The package is ONLY avaliable for 23.04 and 23.10 as you can see on the packages list. So upgrading to 23.04 is an option too. No idea if you can install the 23.04 version into 20.04 (the dependency list seems to be OK)