Unmodified M4A Stream from Youtube ?

[Shabinder]

describe the feature you'd like to see

Using below config, I expect a m4a stream, but I get a mp3 one, How to get a unprocessed stream just proxied from YT ?

{
    "url": "SOME_URL",
    "downloadMode": "audio",
    "youtubeVideoCodec": "h264",
    "youtubeHLS": false,
    "disableMetadata": true,
    "filenameStyle": "nerdy"
}

OR

{
    "url": "SOME_URL",
    "downloadMode": "audio",
    "filenameStyle": "nerdy"
}