How to completely remove the AtomEditor package from the apt-repository? [duplicate]

$ sudo apt update...Ign:6 https://packagecloud.io/AtomEditor/atom/any any InRelease      Err:8 https://packagecloud.io/AtomEditor/atom/any any Release                    404  Not Found [IP: 52.8.40.176 443]E: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.N: Updating from such a repository can't be done securely, and is therefore disabled by default.N: See apt-secure(8) manpage for repository creation and user configuration details.

How do I resolve this update issue?

The AtomEditor was previously installed in this system but was removed after it was discontinued. Seems that the removal is incomplete despite not appearing in Software & Updates - Other Software.

There is an associated question but I can't use it's answer because as I have shown above I don't have the ppa path for Atom that I can use with the ppa-purge command.

Can you provide me with the exact command(s) I need to give to resolve this issue? I have tried these commands but non of them works:

$ sudo ppa-purge [ppa:]https://packagecloud.io/AtomEditor/atomUpdating packages listsE: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.Warning:  apt-get update failed for some reason$ sudo ppa-purge [ppa:]packagecloud.io/AtomEditor/atomUpdating packages listsE: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.Warning:  apt-get update failed for some reason$ sudo ppa-purge [ppa:]AtomEditor/atomUpdating packages listsE: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.Warning:  apt-get update failed for some reason$ sudo ppa-purge ppa:packagecloud.io/AtomEditor/atomUpdating packages listsE: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.Warning:  apt-get update failed for some reason$ sudo ppa-purge ppa:AtomEditor/atomUpdating packages listsE: The repository 'https://packagecloud.io/AtomEditor/atom/any any Release' no longer has a Release file.Warning:  apt-get update failed for some reason

Answer:

Given that none of the answers in the cited duplicate questions answered my question, I opine that my question should not have been closed so that someone could have provided an answer. In any case, I will provide my answer to my question here hoping it will help others facing similar issues.

I discovered that the following legacy files caused the issue:

/etc/apt/sources.list.d/atom.list/etc/apt/sources.list.d/atom.list.save

They contained the instructions that are looked up during sudo apt update:

deb [arch=amd64 signed-by=/usr/share/keyrings/atom.gpg] https://packagecloud.io/AtomEditor/atom/any/ any main

for the "sunset" Atom package. Simply deleting these files solved my issue.

In conclusion, the way to manage the updating issue from legacy packages is to check the folder /etc/apt/sources.list.d/ for the corresponding legacy update files and have them deleted using the sudo rm command.

Clarification: The above-mentioned solution works with Ubuntu 22.04. For earlier versions, please see the comment by @ahmedhamdy.