Hey, I tried embedding audio in my devlog using HTML:

<audio controls="" src="[FILENAME]"></audio>

It works perfectly fine in the editor. But then when I save it, it reverts to plain text. Is there anything I can do about that?

Between the editor and the save, the code is sanitized.

I'm not sure which code is allowed and which is not, but from what you say, it's possible that audio control is not supported.