A PHP-FPM installation can serve several sites using distinct pools. Each pool can specify its listen address, process-manager mode, worker count, environment and PHP configuration overrides. Pool files commonly live under an FPM configuration directory whose exact path depends on the package and operating system.
Different pools help isolate applications operationally, but they do not automatically imply separate PHP binaries. Pools managed by one FPM master commonly use the same underlying runtime version. Multiple installed FPM versions, however, can create genuinely different runtime inventories on one host.
A pool can set php_value and php_admin_value entries. An admin-enforced value cannot be overridden by ordinary application code. Checking only php.ini can miss values supplied by pool configuration, and checking only the CLI can miss the pool altogether.
Map each virtual host to its FPM socket, record the managing service and active settings, then verify the pool that actually serves the application.