How to distinguish packages coming from installation?

[corradoventu]

Ubuntu Version: 26.04
Desktop Environment: GNOME.

Problem Description:
How do I know if a package (eg file-roller) comes from installation or was installed ‘by hand’?

[guiverc]

What I’d explore (probably) is the following

• What media did I install

guiverc@d7050-next:~/uwn/issues/934$   cat /var/log/installer/media-info 
Lubuntu 25.10 "Questing Quokka" - Daily amd64 (20250603)

then look at the Lubuntu questing manifest to see if I’d expect it; whilst installer options can mean not all packages on the manifest are installed (eg. minimal install is selected), and not all are installed anyway (eg. installer won’t be on installed system) etc.. it’s a clue.

This provides me with an indication anyway…

• Ask my system for details

guiverc@d7050-next:~/uwn/issues/934$   apt info file-roller
Package: file-roller
Version: 44.6-3
Priority: optional
Section: gnome
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 1,831 kB
Depends: bzip2, dconf-gsettings-backend | gsettings-backend, libadwaita-1-0 (>= 1.2), libarchive13t64 (>= 3.3.3), libc6 (>= 2.38), libglib2.0-0t64 (>= 2.80.0), libgtk-4-1 >
Recommends: gvfs, yelp
Suggests: arj, lha, lzip, lzma, lzop, ncompress, rpm2cpio, rzip, sharutils, squashfs-tools, unace, unalz, unar, xz-utils, 7zip
Homepage: https://gitlab.gnome.org/GNOME/file-roller
Task: ubuntu-desktop, ubuntu-budgie-desktop-minimal, ubuntu-budgie-desktop, ubuntu-budgie-desktop-raspi, ubuntu-unity-desktop, ubuntucinnamon-desktop-minimal, ubuntucinnam>
Download-Size: 262 kB
APT-Manual-Installed: no
APT-Sources: http://archive.ubuntu.com/ubuntu resolute/main amd64 Packages
Description: archive manager for GNOME
 File-roller is an archive manager for the GNOME environment. It allows you to:
...

where the most critical detail in that is

APT-Manual-Installed: no

and I could also ask for more such as

guiverc@d7050-next:~/uwn/issues/934$   apt why file-roller
file-roller:amd64 is selected for install because:
1. ubuntu-desktop:amd64 is selected for install
2. ubuntu-desktop:amd64 Recommends file-roller

If I wanted confirmation, I could repeat what I did earlier with ubuntu-desktop, ie.

guiverc@d7050-next:~/uwn/issues/934$   apt info ubuntu-desktop
Package: ubuntu-desktop
Version: 1.567
Priority: optional
Section: metapackages
Source: ubuntu-meta
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
...
APT-Manual-Installed: yes

I know I added ubuntu-desktop to this system; thus I’d explore no further.

There well be many other ways, possibly even shorter, but that’s how I’d probably explore for my own packages/system.