[horde] FRAMEWORK_6_0 update: Horde\\Core\\Config\\MotdLoader class does not exist

[Admin Beckspaced]

Hello there,

I am seeing a reproducible error after updating Horde from the 
FRAMEWORK_6_0 branch.

Environment:

openSUSE Leap 16.0
PHP 8.4.24 (NTS)
Apache 2.4.66 (Linux/SUSE)

Known-working state:

horde/horde: dev-FRAMEWORK_6_0 9b4c208

Horde works normally in this state. I tested the login, Horde 
administration and IMP, including successfully sending an email.

Running:

composer update

currently performs exactly these three updates:

horde/horde: dev-FRAMEWORK_6_0 9b4c208 → dev-FRAMEWORK_6_0 8a624b7
horde/imp: dev-FRAMEWORK_6_0 3852464 → dev-FRAMEWORK_6_0 3a07a96
horde/yaml: v3.0.1 → v3.0.2

Immediately after the update, accessing Horde fails with:

Cannot create Horde\Core\Config\MotdLoader

The root cause is:

ReflectionException: Class "Horde\Core\Config\MotdLoader" does not exist 
in 
/srv/www/horde/httpdocs/vendor/horde/injector/src/Binder/Implementation.php:82

The exception is reported at line 499 of:

/srv/www/horde/httpdocs/vendor/horde/injector/src/Injector.php

I checked the installed vendor tree. The updated Horde code contains the 
following reference in vendor/horde/horde/login.php:

$injector->getInstance(Horde\Core\Config\MotdLoader::class)->load();

However, I cannot find a Horde\Core\Config\MotdLoader class anywhere in 
the installed vendor tree.

I then restored the complete Horde installation to the state immediately 
before the Composer update (horde/horde commit 9b4c208). Horde worked 
again without the error.

To verify that the issue was reproducible, I ran the Composer update 
once more from this known-working state. The same three packages were 
updated, and the same MotdLoader error occurred again immediately 
afterwards.

Restoring the known-working state a second time resolved the error again.

horde-db-migrate reports no pending database schema changes; all current 
and ending schema versions are identical.

The issue therefore appears to be reproducible with the current 
FRAMEWORK_6_0 update.

Is Horde\Core\Config\MotdLoader currently missing from one of the 
FRAMEWORK_6_0 packages, or is another dependency/update required?

Best regards
Becki