Bug#1102258: update of keyboard-configuration *partially* overwrote customization of /etc/default/keyboard
Package: keyboard-configuration
An update *partially* overwrote customization of /etc/default/keyboard.
There is no .dpkg-old (nor .dpkg-new) file:
/etc/default# ls key*
keyboard
An update of the package 'keyboard-configuration' occurred at the time 
that the configuration changed:
/var/log/apt/history.log:
Start-Date: 2025-04-05  19:56:58
Upgrade: ...,keyboard-configuration:amd64 (1.235, 1.236),...
A diff of the config from a snapshot created by an apt pre-invoke hook 
immediately before keyboard-configuration was updated, compared to the 
next snapshot taken:
diff -u root.20250405T195656-0700/etc/default/keyboard 
root.20250405T202859-0700/etc/default/keyboard
--- root.20250405T195656-0700/etc/default/keyboard      2025-03-31 
11:36:13.516758707 -0700
+++ root.20250405T202859-0700/etc/default/keyboard      2025-04-05 
19:58:16.629410505 -0700
@@ -25,6 +25,6 @@
 # double shift = capslock
 # single shift = release capslock
 # Add back ctrl-alt-bksp to kill X server
-XKBOPTIONS="ctrl:nocaps,shift:both_capslock_cancel,terminate:ctrl_alt_bksp"
+XKBOPTIONS="terminate:ctrl_alt_bksp"
 BACKSPACE="guess"
I reverted my config, but this behavior was both unexpected and 
destructive.
IIRC, I used 'dpkg-reconfigure keyboard-configuration' to initially add 
"terminate:ctrl_alt_bksp", while all other changes were made by directly 
editing /etc/default/keyboard.
cat /etc/debian_version
trixie/sid
Full list of packages that were updated at the same time as 
keyboard-configuration (as well as logfile context showing they were the 
only packages updated during the period of the snapshots used for the 
diff of /etc/default/keyboard, above):
Start-Date: 2025-04-05  19:56:58
Commandline: apt upgrade
Install: linux-kbuild-6.12.21:amd64 (6.12.21-1, automatic), 
linux-image-6.12.21-amd64:amd64 (6.12.21-1, automatic), 
linux-headers-6.12.21-amd64:amd64 (6.12.21-1, automatic), 
android-udev-rules:amd64 (0~20250314+ds-2, automatic), 
linux-headers-6.12.21-common:amd64 (6.12.21-1, automatic)
Upgrade: python3-apparmor:amd64 (4.1.0~beta5-5, 4.1.0~beta5-6), 
console-setup:amd64 (1.235, 1.236), libdrm-dev:amd64 (2.4.124-1, 
2.4.124-2), android-liblog:amd64 (1:34.0.5-11, 1:34.0.5-12), 
qt6-wayland:amd64 (6.8.2-3, 6.8.2-4), calibre-bin:amd64 (8.1.1+ds-1, 
8.2.1+ds-1), adb:amd64 (1:34.0.5-11, 1:34.0.5-12), 
libqt6wlshellintegration6:amd64 (6.8.2-3, 6.8.2-4), libfwupd3:amd64 
(2.0.7-2, 2.0.7-4), apparmor:amd64 (4.1.0~beta5-5, 4.1.0~beta5-6), 
libdrm-nouveau2:amd64 (2.4.124-1, 2.4.124-2), libapparmor1:amd64 
(4.1.0~beta5-5, 4.1.0~beta5-6), linux-headers-amd64:amd64 (6.12.20-1, 
6.12.21-1), apparmor-utils:amd64 (4.1.0~beta5-5, 4.1.0~beta5-6), 
qtwayland5:amd64 (5.15.15-2, 5.15.15-3), libqt5waylandcompositor5:amd64 
(5.15.15-2, 5.15.15-3), console-setup-linux:amd64 (1.235, 1.236), 
libdrm-common:amd64 (2.4.124-1, 2.4.124-2), android-libbase:amd64 
(1:34.0.5-11, 1:34.0.5-12), linux-image-amd64:amd64 (6.12.20-1, 
6.12.21-1), android-libcutils:amd64 (1:34.0.5-11, 1:34.0.5-12), 
android-libziparchive:amd64 (1:34.0.5-11, 1:34.0.5-12), calibre:amd64 
(8.1.1+ds-1, 8.2.1+ds-1), bpftool:amd64 (7.5.0+6.12.20-1, 
7.5.0+6.12.21-1), python3-libapparmor:amd64 (4.1.0~beta5-5, 
4.1.0~beta5-6), installation-report:amd64 (2.94, 2.95), 
libqt6waylandcompositor6:amd64 (6.8.2-3, 6.8.2-4), 
libqt6waylandclient6:amd64 (6.8.2-3, 6.8.2-4), libdrm-amdgpu1:amd64 
(2.4.124-1, 2.4.124-2), libdrm-radeon1:amd64 (2.4.124-1, 2.4.124-2), 
libdrm2:amd64 (2.4.124-1, 2.4.124-2), keyboard-configuration:amd64 
(1.235, 1.236), libdc1394-25:amd64 (2.2.6-4+b2, 2.2.6-5), 
android-sdk-platform-tools-common:amd64 (28.0.2+11, 28.0.2+12), 
libqt5waylandclient5:amd64 (5.15.15-2, 5.15.15-3), libdrm-intel1:amd64 
(2.4.124-1, 2.4.124-2), fwupd:amd64 (2.0.7-2, 2.0.7-4), 
linux-libc-dev:amd64 (6.12.20-1, 6.12.21-1)
End-Date: 2025-04-05  19:58:47
Start-Date: 2025-04-05  20:29:01
Commandline: apt autoremove
Remove: linux-image-6.12.19-amd64:amd64 (6.12.19-1), 
linux-kbuild-6.12.19:amd64 (6.12.19-1), 
linux-headers-6.12.19-amd64:amd64 (6.12.19-1), 
linux-headers-6.12.19-common:amd64 (6.12.19-1), 
android-sdk-platform-tools-common:amd64 (28.0.2+12)
End-Date: 2025-04-05  20:29:05
Start-Date: 2025-04-06  10:55:06
Commandline: /usr/bin/unattended-upgrade
Upgrade: python3-aiohttp:amd64 (3.10.11-1+b1, 3.11.15-1)
End-Date: 2025-04-06  10:55:09
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