Package "usr-is-merged" is reported as missing in Debian Live ISO 12.5 (debian-live-12.5.0-amd64-lxqt.iso) during installation with live-installer/enable=false

Hello,

The "Normal" [0] Debian Installer included in Debian Live ISO 12.5 
(debian-live-12.5.0-amd64-lxqt.iso) fails the installation of the base 
system  when started with the following preseed parameters:

	live-installer/enable=false firmware=never

The Debian installer stops deboostrap with the following error

	Could not find these debs: usr-is-merged

The installation of the base system is not completed even if the 
base-install step is repeated.

The syslog contains:

[..]
May  1 17:17:12 main-menu[440]: INFO: Menu item 'bootstrap-base' selected
May  1 17:17:13 debootstrap: /usr/sbin/debootstrap --components=main 
--debian-installer --resolve-deps --no-check-gpg bookworm /target 
file:///cdrom/
May  1 17:18:26 base-installer: error: exiting on error 
base-installer/debootstrap-failed
May  1 17:19:22 main-menu[440]: WARNING **: Configuring 'bootstrap-base' 
failed with error code 1
May  1 17:19:22 main-menu[440]: WARNING **: Menu item 'bootstrap-base' 
failed.
[..]

The package "usr-is-merged" 
(https://packages.debian.org/bookworm/usr-is-merged) is missing in 
/cdrom/pool/main/u :

ls -l /cdrom/pool/main/u/
dr-xr-xr-x    1 root     root          2048 Feb 10 11:07 ucf
dr-xr-xr-x    1 root     root          2048 Feb 10 11:07 usrmerge

Which package should I report to the bug tracking system ?

Let me know if I can help.

Thanks.

--
[0] 
https://live-team.pages.debian.net/live-manual/html/live-manual/customizing-installer.en.html