PHP - Help Interpreting Print_r Result...

The following script comes from create a decorator example.  Please take a look at  __construct() and $pathItem.  Doesn't look like any PHP I've ever seen.  Agree?  I don't think it matters and just stating so to make sure, but I am not using a docket but have api-platform on the local server.  I've gotten all to work until now.

<?php
// api/src/OpenApi/JwtDecorator.php

declare(strict_types=1);

namespace App\OpenApi;

use ApiPlatform\Core\OpenApi\Factory\OpenApiFactoryInterface;
use ApiPlatform\Core\OpenApi\OpenApi;
use ApiPlatform\Core\OpenApi\Model;

final class JwtDecorator implements OpenApiFactoryInterface
{
    public function __construct(
        private OpenApiFactoryInterface $decorated
    ) {}

    public function __invoke(array $context = []): OpenApi
    {
        $openApi = ($this->decorated)($context);
        $schemas = $openApi->getComponents()->getSchemas();

        $schemas['Token'] = new ArrayObject([
            'type' => 'object',
            'properties' => [
                'token' => [
                    'type' => 'string',
                    'readOnly' => true,
                ],
            ],
        ]);
        $schemas['Credentials'] = new ArrayObject([
            'type' => 'object',
            'properties' => [
                'email' => [
                    'type' => 'string',
                    'example' => 'johndoe@example.com',
                ],
                'password' => [
                    'type' => 'string',
                    'example' => 'apassword',
                ],
            ],
        ]);

        $pathItem = new Model\PathItem(
            ref: 'JWT Token',
            post: new Model\Operation(
                operationId: 'postCredentialsItem',
                responses: [
                    '200' => [
                        'description' => 'Get JWT token',
                        'content' => [
                            'application/json' => [
                                'schema' => [
                                    '$ref' => '#/components/schemas/Token',
                                ],
                            ],
                        ],
                    ],
                ],
                summary: 'Get JWT token to login.',
                requestBody: new Model\RequestBody(
                    description: 'Generate new JWT Token',
                    content: new ArrayObject([
                        'application/json' => [
                            'schema' => [
                                '$ref' => '#/components/schemas/Credentials',
                            ],
                        ],
                    ]),
                ),
            ),
        );
        $openApi->getPaths()->addPath('/authentication_token', $pathItem);

        return $openApi;
    }
}

I am thinking that maybe the constructor needs to be changed to:

    private $decorated;
    public function __construct(OpenApiFactoryInterface $decorated)
    {
        $this->decorated = $decorated;
    }

Regarding $pathItem, Model\PathItem's constructor is as follows.  Any thoughts on what they are suggesting?  Thanks

    public function __construct(
        string $ref = null, 
        string $summary = null, 
        string $description = null,
        Operation $get = null, 
        Operation $put = null, 
        Operation $post = null,
        Operation $delete = null,
        Operation $options = null,
        Operation $head = null,
        Operation $patch = null, 
        Operation $trace = null,
        ?array $servers = null,
        array $parameters = []
    )
    {/* ... */}

After switching from PHP 5.3 on Windows Server 2003 to PHP 7.4.3 on Linux Mint 19.3 (Tricia Cinnamon), I find that the output of print_r() has changed.

If we look at the documentation (https://www.php.net/manual/en/function.print-r.php), the provided example output is as it was on my earlier machine:

<pre>
Array
(
    [a] => apple
    [b] => banana
    [c] => Array
        (
            [0] => x
            [1] => y
            [2] => z
        )
)
</pre>

However, on the second machine, the output is:

<pre>
Array
(
    [a] => apple
    [b] => banana
    [c] => Array
        (
            [0] => x
            [1] => y
            [2] => z
        )
<blank line>
)
</pre>

Note the unexpected new line after each recursed array's closing parenthesis. The new line is not present after the outermost array closing parenthesis.

Also to note, there is a newer version of XDebug installed.

My question is: Is this a bug? (Follow-on question: if possible to determine at which version the output changed, what version would that be?)

This difference is causing existing code to not be able to correctly parse that output.