Podcasting with JSON Feed

Experiment to extend JSON Feed at the top-level object with extra fields that might traditionally have been in RSS itunes tags:

"_podcast": {
    "about": "https://jsonfeed.org/podcasting",
    "image": "https://example.org/cover.png",
    "explicit": false,
    "categories": [
        {
            "category": "Society \u0026 Culture",
            "subcategory": "Personal Journals"
        }
    ]
}