Core pipeline is failing

[Golem28]

The following problem blocks our core pipeline:

Invalid get_string() identifier: 'cachedef_discovery' or component 'assignsubmission_collabora'.
Perhaps you are missing $string['cachedef_discovery'] = '';
in /var/www/public_html/mod/assign/submission/collabora/lang/en/assignsubmission_collabora.php?        

line 355 of /lib/classes/string_manager_standard.php: call to debugging()        
line 194 of /lib/classes/lang_string.php: call to core_string_manager_standard->get_string()        
line 229 of /lib/classes/lang_string.php: call to core\lang_string->get_string()        
line ? of unknownfile: call to core\lang_string->__toString()        
line 212 of /lib/classes/collator.php: call to Collator->asort()        
line 322 of /lib/classes/collator.php: call to core_collator::asort()        
line 236 of /cache/classes/output/renderer.php: call to core_collator::asort_array_of_arrays_by_key()        
line 825 of /cache/classes/local/administration_display_helper.php: call to core_cache\output\renderer->definition_summaries()        
line 84 of /cache/admin.php: call to core_cache\local\administration_display_helper->generate_admin_page()

It occurs in the Moodleversion 4.5 and the pluginversion 2025030401