While running phpbbcli.php
like described in https://www.phpbb.com/support/docs/en/3.3/kb/article/phpbb-32%2B-text-reparser/ to enable / disable an extension like e.g.
the following errors where showing up in my PHP error logs:
Additionally the following feedback on disabling / enabling the extension is missing:
If i'm understanding the message correctly this is originating from having APCu configured for phpBB and from the default of PHP / APCu not enabling APCu for the CLI version of PHP:
While setting apc.enable_cli to 1 would hide this message the manual linked above is saying that this should mostly be done for testing and debugging purposes.
Instead of requiring to have this functionality enabled phpBB could disable the usage of APCu for phpbbcli.php completely (PHP_SAPI === 'cli').