downloaded packages are removed just after installation

[Jérôme Bouat]

When installing a package with 'apt install [package name]', I see the deb files which appear in /var/cache/apt/archives.
However, just after installation, the deb file are deleted from this directory.
I would prefer a deletion after a few days. Sometimes, we install/uninstall and reinstall.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: apt 2.4.5
ProcVersionSignature: Ubuntu 5.15.0-25.25-generic 5.15.30
Uname: Linux 5.15.0-25-generic x86_64
ApportVersion: 2.20.11-0ubuntu82
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: XFCE
Date: Sun Apr 24 16:10:48 2022
InstallationDate: Installed on 2022-04-24 (0 days ago)
InstallationMedia: Xubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
SourcePackage: apt
UpgradeStatus: No upgrade log present (probably fresh install)

[David Kalnischkies (donkult)]

apt 1.2~exp1 came with the follow NEWS entry:
  [ Automatic removal of debs after install ]
  After packages are successfully installed by apt(8),
  the corresponding .deb package files will be
  removed from the /var/cache/apt/archives cache directory.

  This can be changed by setting the apt configuration option
    "Binary::apt::APT::Keep-Downloaded-Packages" to "true". E.g:

  # echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' \
      > /etc/apt/apt.conf.d/01keep-debs

  Please note that the behavior of apt-get is unchanged. The
  downloaded debs will be kept in the cache directory after they
  are installed. To enable the behavior for other tools, you can set
  "APT::Keep-Downloaded-Packages" to false.

If you have disabled this feature you can do manual maintenance with the `autoclean` and `clean` commands. More automatic maintenance can be achieved with our cronjob, see `/usr/lib/apt/apt.systemd.daily`for details, which can e.g. be configured to remove files after a few days as you seem to prefer here.

As this default behavior is a deliberate choice and there are various options to change this I am closing this report as not a bug.