> The output should be encoded as a pretty JSON string.

...

> Your parser should store the following output in $outputPath as a JSON file:

    {
        "\/blog\/11-million-rows-in-seconds": {
            "2025-01-24": 1,
            "2026-01-24": 2
        },
        "\/blog\/php-enums": {
            "2024-01-24": 1
        }
    }

They don't define what exactly "pretty" means, but superflous escapes are not very pretty in my opinion.