Looks like the dahdi kernel module didn't clean up correctly after kernel update:
Just cruft... no super big deal...
w0cra@node59468:~ $ sudo apt update
Hit:1 Index of /debian bookworm InRelease
Hit:2 Index of /debian-security bookworm-security InRelease
Hit:3 Index of /debian bookworm-updates InRelease
Hit:4 Index of /DVSwitch_Repository bookworm InRelease
Hit:5 Index of /debian bookworm InRelease
Hit:6 Index of /public/ bookworm InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
w0cra@node59468:~ $ sudo apt full-upgrade
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
linux-headers-6.1.0-32-arm64 linux-headers-6.1.0-32-common
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
w0cra@node59468:~ $ sudo apt autopurge
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages will be REMOVED:
linux-headers-6.1.0-32-arm64* linux-headers-6.1.0-32-common*
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
After this operation, 62.0 MB disk space will be freed.
Do you want to continue? [Y/n]
(Reading database ... 136383 files and directories currently installed.)
Removing linux-headers-6.1.0-32-arm64 (6.1.129-1) ...
dpkg: warning: while removing linux-headers-6.1.0-32-arm64, directory '/lib/modules/6.1.0-32-arm64' not empty so not removed
Removing linux-headers-6.1.0-32-common (6.1.129-1) ...
w0cra@node59468:~ $ ls -lart /lib/mod
modprobe.d/ modules/ modules-load.d/
w0cra@node59468:~ $ ls -lart /lib/modules/6.1.0-32-arm64/
total 40
drwxr-xr-x 3 root root 4096 Mar 31 22:59 updates
-rw-r--r-- 1 root root 1996 Mar 31 22:59 modules.symbols.bin
-rw-r--r-- 1 root root 1766 Mar 31 22:59 modules.symbols
-rw-r--r-- 1 root root 55 Mar 31 22:59 modules.softdep
-rw-r--r-- 1 root root 0 Mar 31 22:59 modules.devname
-rw-r--r-- 1 root root 266 Mar 31 22:59 modules.dep.bin
-rw-r--r-- 1 root root 129 Mar 31 22:59 modules.dep
-rw-r--r-- 1 root root 0 Mar 31 22:59 modules.builtin.bin
-rw-r--r-- 1 root root 0 Mar 31 22:59 modules.builtin.alias.bin
-rw-r--r-- 1 root root 43 Mar 31 22:59 modules.alias.bin
-rw-r--r-- 1 root root 69 Mar 31 22:59 modules.alias
drwxr-xr-x 10 root root 4096 Apr 28 16:02 ..
drwxr-xr-x 3 root root 4096 Apr 28 18:37 .
w0cra@node59468:~ $ ls -lart /lib/modules/6.1.0-32-arm64/updates/
total 12
drwxr-xr-x 3 root root 4096 Mar 31 22:59 .
drwxr-xr-x 2 root root 4096 Mar 31 22:59 dkms
drwxr-xr-x 3 root root 4096 Apr 28 18:37 ..
w0cra@node59468:~ $ ls -lart /lib/modules/6.1.0-32-arm64/updates/dkms/
total 284
drwxr-xr-x 3 root root 4096 Mar 31 22:59 ..
-rw-r--r-- 1 root root 12109 Mar 31 22:59 dahdi_dummy.ko
-rw-r--r-- 1 root root 244333 Mar 31 22:59 dahdi.ko
-rw-r--r-- 1 root root 21397 Mar 31 22:59 dahdi_transcode.ko
drwxr-xr-x 2 root root 4096 Mar 31 22:59 .