Because of something I did during an anthropology lecture, I learned the hard way to read the "The following packages will be REMOVED" list when upgrading a package to backports in Debian GNU + Linux.

I upgraded pipewire from stable to backports (I want to know ~~if this is related to my problem~~ why essential packages were removed)

Start-Date: 2024-09-18  14:59:02
Commandline: apt install libpipewire-0.3-0/bookworm-backports
Requested-By: dullbananas (1000)
Install: libpulsedsp:amd64 (16.1+dfsg1-2+b1, automatic), pulseaudio:amd64 (16.1+dfsg1-2+b1, automatic), pulseaudio-utils:amd64 (16.1+dfsg1-2+b1, automatic), libasound2-plugins:amd64 (1.2.7.1-1, automatic), policykit-1-gnome:amd64 (0.105-8, automatic), pulseaudio-module-bluetooth:amd64 (16.1+dfsg1-2+b1, automatic), libspeexdsp1:amd64 (1.2.1-1, automatic)
Upgrade: libspa-0.2-modules:amd64 (0.3.65-3+deb12u1, 1.2.3-1~bpo12+1), libpipewire-0.3-0:amd64 (0.3.65-3+deb12u1, 1.2.3-1~bpo12+1)
Remove: pipewire-pulse:amd64 (0.3.65-3+deb12u1), pipewire-audio-client-libraries:amd64 (0.3.65-3+deb12u1), t2-apple-audio-dsp-speakers161:amd64 (0.2.0-1), gnome:amd64 (1:43+1), gnome-remote-desktop:amd64 (43.3-1), pipewire:amd64 (0.3.65-3+deb12u1), gnome-shell-extensions:amd64 (43.1-1), gnome-shell:amd64 (43.9-0+deb12u2), pipewire-tests:amd64 (0.3.65-3+deb12u1), gdm3:amd64 (43.0-3), libspa-0.2-jack:amd64 (0.3.65-3+deb12u1), libspa-0.2-bluetooth:amd64 (0.3.65-3+deb12u1), pipewire-jack:amd64 (0.3.65-3+deb12u1), gstreamer1.0-pipewire:amd64 (0.3.65-3+deb12u1), t2-apple-audio-dsp-mic:amd64 (0.4.0-1), pipewire-audio:amd64 (0.3.65-3+deb12u1), pipewire-bin:amd64 (0.3.65-3+deb12u1), chrome-gnome-shell:amd64 (42.1-3), task-gnome-desktop:amd64 (3.73), gnome-session:amd64 (43.0-1+deb12u1), gnome-browser-connector:amd64 (42.1-3), gnome-core:amd64 (1:43+1), libpipewire-0.3-modules:amd64 (0.3.65-3+deb12u1), wireplumber:amd64 (0.4.13-1), gnome-shell-extension-prefs:amd64 (43.9-0+deb12u2), pipewire-alsa:amd64 (0.3.65-3+deb12u1)
End-Date: 2024-09-18  14:59:35

Start-Date: 2024-09-18  14:59:43
Commandline: apt install libpipewire-0.3-modules/bookworm-backports
Requested-By: dullbananas (1000)
Install: libconfig++9v5:amd64 (1.5-0.4, automatic), libxml++2.6-2v5:amd64 (2.40.1-3, automatic), libpipewire-0.3-modules:amd64 (1.2.3-1~bpo12+1), libffado2:amd64 (2.4.7-1, automatic)
End-Date: 2024-09-18  14:59:48

Start-Date: 2024-09-18  14:59:57
Commandline: apt install pipewire/bookworm-backports
Requested-By: dullbananas (1000)
Install: pipewire:amd64 (1.2.3-1~bpo12+1), pipewire-bin:amd64 (1.2.3-1~bpo12+1, automatic), wireplumber:amd64 (0.4.13-1, automatic)
End-Date: 2024-09-18  15:00:02

I suspended the computer, and after resume, the lock screen was broken:

When I clicked on the password field, the text cursor only appeared for a split second, and I could not type in it
Clicking on the user switch button on the bottom right corner did nothing
A few times, the text “Authentication error” randomly appeared for a split second, probably for 1 frame
No way to reboot the normal way, because I could only use the power menu on the lock screen, which only has suspend

I used the power button to reboot, and instead of GNOME, there was darkness

Debian GNU/Linux 12 dullbananas-macbookpro161 tty1

dullbananas-macbookpro161 login:

I downgraded pipewire to stable

Start-Date: 2024-09-18  15:20:16
Commandline: apt install pipewire/stable
Requested-By: dullbananas (1000)
Downgrade: pipewire:amd64 (1.2.3-1~bpo12+1, 0.3.65-3+deb12u1), pipewire-bin:amd64 (1.2.3-1~bpo12+1, 0.3.65-3+deb12u1), libspa-0.2-modules:amd64 (1.2.3-1~bpo12+1, 0.3.65-3+deb12u1), libpipewire-0.3-modules:amd64 (1.2.3-1~bpo12+1, 0.3.65-3+deb12u1), libpipewire-0.3-0:amd64 (1.2.3-1~bpo12+1, 0.3.65-3+deb12u1)
End-Date: 2024-09-18  15:20:26

I ran dpkg --verify and got this output

??5??????   /lib/modules/6.10.9-1-t2-bookworm/modules.alias
??5??????   /lib/modules/6.10.9-1-t2-bookworm/modules.alias.bin
??5??????   /lib/modules/6.10.9-1-t2-bookworm/modules.dep
??5??????   /lib/modules/6.10.9-1-t2-bookworm/modules.dep.bin
missing     /usr/share/dbus-1/services/io.snapcraft.Prompt.service
??5?????? c /etc/systemd/logind.conf
??5?????? c /etc/tlp.conf
??5??????   /lib/modules/6.10.8-1-t2-bookworm/modules.alias
??5??????   /lib/modules/6.10.8-1-t2-bookworm/modules.alias.bin
??5??????   /lib/modules/6.10.8-1-t2-bookworm/modules.dep
??5??????   /lib/modules/6.10.8-1-t2-bookworm/modules.dep.bin
??5?????? c /etc/gdm3/daemon.conf
missing     /etc/os-release.debootstrap
??5??????   /lib/modules/6.10.7-1-t2-bookworm/modules.alias
??5??????   /lib/modules/6.10.7-1-t2-bookworm/modules.alias.bin
??5??????   /lib/modules/6.10.7-1-t2-bookworm/modules.dep
??5??????   /lib/modules/6.10.7-1-t2-bookworm/modules.dep.bin

I reinstalled systemd (not sure if this made a difference)

Start-Date: 2024-09-18  15:48:58
Commandline: apt install --reinstall systemd
Requested-By: dullbananas (1000)
Reinstall: systemd:amd64 (252.30-1~deb12u2)
End-Date: 2024-09-18  15:49:02

I reinstalled gdm3, and immediately without me doing anything else, there was GNOME instead of darkness

Start-Date: 2024-09-18  15:51:49
Commandline: apt install --reinstall gdm3
Requested-By: dullbananas (1000)
Install: gnome-remote-desktop:amd64 (43.3-1, automatic), gnome-shell:amd64 (43.9-0+deb12u2, automatic), power-profiles-daemon:amd64 (0.12-1+b1, automatic), gdm3:amd64 (43.0-3), gstreamer1.0-pipewire:amd64 (0.3.65-3+deb12u1, automatic), chrome-gnome-shell:amd64 (42.1-3, automatic), gnome-session:amd64 (43.0-1+deb12u1, automatic), gnome-browser-connector:amd64 (42.1-3, automatic), gnome-shell-extension-prefs:amd64 (43.9-0+deb12u2, automatic)
Remove: tlp:amd64 (1.5.0-2), tlp-rdw:amd64 (1.5.0-2)
End-Date: 2024-09-18  15:52:05

End of class
I reinstalled tlp because installing gdm3 removed it
After selecting an app search result, instead of a new window opening, an existing window was focused, and this led to me discovering that my built-in extensions were gone
While writing this post, I got the idea of using the list of removed packages in the apt history log output from apt install libpipewire-0.3-0/bookworm-backports to see what packages to install again, so I did that, then I also had to uninstall firefox-esr again
I rebooted, and my built-in extensions and other stuff were resurrected, so now I have full redemption
Another Window Session Manager restored my windows in a way that pissed me off

(Failed attempts of recovery are not listed)

Edit: actually I made the mistake 1 minute before the start of class