Adam appcd 2.2.1 which also releases in the next few days will default PHP error logs to the home directory. It also sends the php-fpm error log there, although this might be of limited value.
It's of limited value if you don't set catch_workers_output
to yes, the default is no.
https://community.enhance.com/d/2084-set-catch-workers-output-for-php-fpm-to-yes-by-default