apt-get update returns errors

Question

Executing this command returns:

apt-get update
Hit:1 http://kali.download/kali kali-rolling InRelease              
Ign:2 https://download.docker.com/linux/debian kali-rolling InRelease
Err:3 https://download.docker.com/linux/debian kali-rolling Release
  404  Not Found [IP: 65.9.109.36 443]
Reading package lists... Done
E: The repository 'https://download.docker.com/linux/debian kali-rolling Release' does not have 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.

My /etc/apt/sources.list:

# See https://www.kali.org/docs/general-use/kali-linux-sources-list-repositories/
deb http://http.kali.org/kali kali-rolling main contrib non-free

# Additional line for source packages
# deb-src http://http.kali.org/kali kali-rolling main contrib non-free
# deb-src [arch=amd64] https://download.docker.com/linux/debian kali-rolling stable
# deb [arch=amd64] https://download.docker.com/linux/ubuntu ubuntu stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu kali-rolling stable
# deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable
# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable

Answer 1

You probably have a file in /etc/apt/sources.list.d containing an invalid repository definition. Delete that and the error will no longer occur.

Answer 2

E: The repository 'https://download.docker.com/linux/debian kali-rolling Release' does not have a Release file.

Docker doesn't have a release for kali-rolling. You should use debian codnames.

Supported platforms

Users of Debian derivatives such as “BunsenLabs Linux”, “Kali Linux” or “LMDE” (Debian-based Mint) should follow the installation instructions for Debian, substituting the version of their distro for the corresponding Debian release. Refer to the documentation of your distro to find which Debian release corresponds with your derivative version

Install Docker Engine on Debian

echo "deb [arch=amd64] https://download.docker.com/linux/debian buster stable" | \
sudo tee /etc/apt/sources.list.d/docker-ce.list

As said Stephen , delete the file under /etc/apt/sources.list.d which is the root cause of the error.