Formatting code in upsert API changes ">" to HTML escaped version thereof ">"

It seems to me that Talkyard got < in the uploaded CommonMark source already. When I look at the page source, I see:

    //Try to see if waiting for ...
    //so that it would be safe to ...
    retry(() => sf.ui.proTools.  ...

    //Now try clearing it...
    retry(() => {
        var menuItem;

But Talkyard shoulnd't process the source — it just saves it as is, and then converts & sanitizes to HTML.
Now, since < is in the source already, I'm wondering if SoundFlow's server actually sends < to Talkyard.

SoundFlow doesn't do any HTML escaping of its own, before posting to Ty?
Could possibly a React editor component SoundFlow uses, do its own HTML escaping?

---

A bit further down also " gets escaped — I suppose all of < & " get escaped:

    //Close the dialog
        sf.ui.proTools.menuClick({
            menuPath: ["Window", ...],

There's something unusual with how the code block ends — in the CommonMark source, there's this:

}```</code></pre>

So, both ``` and </code></pre>. I would-think-that / wonder-if that was included in the API request from the start already.