What's a "crispy" R?

I never imagined there’s so much of interest surrounding a single letter.

But it turns out…

In November 2021, linguists from around the world met in Lausanne, Switzerland, for the seventh edition of a conference focusing specifically on the “R” sound.

~ Dan Nosowitz from, https://www.atlasobscura.com/articles/what-is-a-crispy-r

I didn’t come away fRom this article with anything in paRticulaR that I wanted to tRy. But I’ve been tRipping oveR some of them now that I’m hypeR awaRe of how inteResting and special the letteR and its vaRious sounds aRe.