system-tools/php_modules.php

<?php
/**
 * Returns all installed (loaded) PHP modules.
 *
 * Usage:
 *   Web: http://host/php_modules.php          -> JSON
 *   CLI: php php_modules.php                  -> JSON
 *        php php_modules.php --plain          -> one module per line
 */

$plain = PHP_SAPI === 'cli'
    ? in_array('--plain', $argv, true)
    : isset($_GET['plain']);

$modules = get_loaded_extensions();
sort($modules, SORT_NATURAL | SORT_FLAG_CASE);

if ($plain) {
    if (PHP_SAPI !== 'cli') {
        header('Content-Type: text/plain; charset=utf-8');
    }
    echo implode(PHP_EOL, $modules), PHP_EOL;
    exit;
}

$result = [
    'php_version' => PHP_VERSION,
    'sapi'        => PHP_SAPI,
    'count'       => count($modules),
    'modules'     => [],
];

foreach ($modules as $module) {
    $version = phpversion($module);
    $result['modules'][$module] = ($version === false || $version === '') ? null : $version;
}

if (PHP_SAPI !== 'cli') {
    header('Content-Type: application/json; charset=utf-8');
}
echo json_encode($result, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES), PHP_EOL;