Haha IDK if it’s officially supported. I just learned about it from a neat embedded demo posted a few days ago. LOL and it is hard to tell it’s a PG, not a screen shot or video. 
There isn’t an icon/form for inserting it, but you can create the iframe tag like below and include it in posts manually. Thanks! 
<iframe src="https://playground.babylonjs.com/#NF6EVB" width="800px" height="600px"></iframe>