我之前在刷新 apt-cache 时遇到过这种情况：
Hit:1 http://archive.ubuntu.com/ubuntu groovy InRelease
Get:2 http://archive.ubuntu.com/ubuntu groovy-updates InRelease [115 kB]
Hit:3 http://ppa.launchpad.net/git-core/ppa/ubuntu disco InRelease
Get:4 http://dl.google.com/linux/chrome/deb stable InRelease [1 811 B]
Get:5 http://apt.postgresql.org/pub/repos/apt groovy-pgdg InRelease [16,8 kB]
Ign:7 http://archive.ubuntu.com/ubuntu groovy-backports InRelease
Ign:8 http://archive.ubuntu.com/ubuntu groovy-security InRelease
Ign:9 http://repo.vivaldi.com/stable/deb stable InRelease
Get:10 https://download.docker.com/linux/ubuntu focal InRelease [36,2 kB]
Hit:11 http://repo.vivaldi.com/stable/deb stable Release
Hit:12 http://archive.ubuntu.com/ubuntu groovy-backports Release
Hit:13 http://archive.ubuntu.com/ubuntu groovy-security Release
Hit:14 https://cli-assets.heroku.com/branches/stable/apt ./ InRelease
Hit:15 https://download.sublimetext.com apt/stable/ InRelease
Ign:6 https://packages.cloud.google.com/apt kubernetes-xenial InRelease
Hit:17 https://packages.cloud.google.com/apt kubernetes-xenial Release
Hit:16 https://packagecloud.io/AtomEditor/atom/any any InRelease
Err:4 http://dl.google.com/linux/chrome/deb stable InRelease
Splitting up /var/lib/apt/lists/partial/dl.google.com_linux_chrome_deb_dists_stable_InRelease into data and signature failed
Err:5 http://apt.postgresql.org/pub/repos/apt groovy-pgdg InRelease
Splitting up /var/lib/apt/lists/partial/apt.postgresql.org_pub_repos_apt_dists_groovy-pgdg_InRelease into data and signature failed
Err:2 http://archive.ubuntu.com/ubuntu groovy-updates InRelease
Splitting up /var/lib/apt/lists/partial/archive.ubuntu.com_ubuntu_dists_groovy-updates_InRelease into data and signature failed
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://dl.google.com/linux/chrome/deb stable InRelease: Splitting up /var/lib/apt/lists/partial/dl.google.com_linux_chrome_deb_dists_stable_InRelease into data and signature failed
W: GPG error: http://apt.postgresql.org/pub/repos/apt groovy-pgdg InRelease: Splitting up /var/lib/apt/lists/partial/apt.postgresql.org_pub_repos_apt_dists_groovy-pgdg_InRelease into data and signature failed
E: The repository 'http://apt.postgresql.org/pub/repos/apt groovy-pgdg InRelease' is no longer signed.
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.
W: GPG error: http://archive.ubuntu.com/ubuntu groovy-updates InRelease: Splitting up /var/lib/apt/lists/partial/archive.ubuntu.com_ubuntu_dists_groovy-updates_InRelease into data and signature failed
E: The repository 'http://archive.ubuntu.com/ubuntu groovy-updates InRelease' is no longer signed.
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.
我已经解决了，但我想知道是否有人知道这些错误是什么意思？我不需要任何解决方案，只需解释这些错误消息？