{
    "ttl": 600000,
    "extensions": {
        "sjs": {
            "handler": "acre_script"
        },
        "js": {
            "handler": "passthrough",
            "media_type": "application/x-javascript"
        },
        "css": {
            "handler": "passthrough",
            "media_type": "text/css"
        },
        "html": {
            "handler": "passthrough",
            "media_type": "text/html"
        },
        "gif": {
            "handler": "binary",
            "media_type": "image/gif"
        },
        "png": {
            "handler": "binary",
            "media_type": "image/png"
        },
        "jpg": {
            "handler": "binary",
            "media_type": "image/jpg"
        },
        "mjt": {
            "handler": "mjt"
        },
        "mql": {
            "handler": "mqlquery"
        }
    }
}

{
    "ttl": 600000,
    "extensions": {
        "sjs": {
            "handler": "acre_script"
        },
        "js": {
            "handler": "passthrough",
            "media_type": "application/x-javascript"
        },
        "css": {
            "handler": "passthrough",
            "media_type": "text/css"
        },
        "json": {
          "handler": "passthrough",
          "media_type": "text/plain"
        },
        "html": {
            "handler": "passthrough",
            "media_type": "text/html"
        },
        "gif": {
            "handler": "binary",
            "media_type": "image/gif"
        },
        "png": {
            "handler": "binary",
            "media_type": "image/png"
        },
        "jpg": {
            "handler": "binary",
            "media_type": "image/jpg"
        },
        "mjt": {
            "handler": "mjt"
        },
        "mql": {
            "handler": "mqlquery"
        }
    }
}

Add .json to the default metadata file
Add .json to the default metadata file