Steps to reproduce the issue

Login to Administrator
System -> Content Languages -> Install Language
Select any language and click the Install button.

Expected result

Language Installs

Actual result

Top of the Page Danger Error - Unable to detect manifest file.

System information (as much as possible)

10.6.23-MariaDB-log

PHP Version 8.4.10

Joomla! Version:
Joomla! 6.0.0-beta3 Beta [ Kuimarisha ] 16-September-2025 16:30 UTC

Joomla Backward Compatibility Plugin:
Disabled

User Agent
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:143.0) Gecko/20100101 Firefox/143.0

Upload Max Filesize
128M

Post Max Size
512M

Memory Limit
512M

Additional comments