On macOS there is a tool called fs_usage
which can be used to see what files are accessed on the system while it is running. It needs sudo to run.
ps aux | grep php-fpm
sudo fs_usage -f "pathname" [pid]
access
checks whether the calling process can access the file pathnameopen
creates a new open file description, an entry in the system-wide table of open filesclose
closes a file descriptorstat64
returns information about a file