support new message type

[dtlnor]

there is "headerSubtext": {"simpleText": "some_msg"} now

[siikamiika]

Do you have a sample live chat (replay) file (or a line of one) where this occurs? The code change makes sense based on your comment.

(by the way, does the yt-dlp downloader still work?)

[dtlnor]

here is the sample chat sample.zip

I use the latest yt-dlp to download it, it still work

(btw a alternative chat downloader here if you are interested https://github.com/xenova/chat-downloader)