Behavior of **a*_b**

Looking at**a*_b**

There seems to be disagreement in the wild:

CommonMark wants **a*_b** to render as


Whereas lots of the established players render as:


Does this double <em> even make sense conceptually, it seems like some weird HTML to me.

I wouldn’t say there is some kind of super consensus on this…

Like everything else with Markdown, it is indeterminate.

Also this is valid HTML5…

<!DOCTYPE html>
<html lang="en">