Certainly, italics in asterisks, but underscores are valid too in plain text, double either to get bold. I wanted the _underscore_ since I was talking about plaintext and didn't want it disappeared, though I *suppose* this works too.

^ means superscript, as footnote numbers are in publishing, but more importantly, https://github.blog/changelog/2021-09-30-footnotes-now-suppo...