Thanks for troubleshooting, @apreshill and @cderv. I have the same emoji face.
To be complete, I tried...
```{r embed-xaringan, echo=FALSE}
xaringanExtra::embed_xaringan(url = "decks/covid-vh-ke/nov2020.html", ratio = "4:3")
```
...and I confirmed that decks/ gets copied to docs when I build the site. But file not found.
Here's what the file structure looks like now:
root
- _posts
- 2020-12-04-tracking-vaccine-hesitancy
- tracking-vaccine-hesitancy.Rmd
- docs
- posts
- 2020-12-04-tracking-vaccine-hesitancy
- index.html
- decks
- covid-vh-ke
- nov2020.html
- decks
- covid-vh-ke
- nov2020.html
I also tried going up 2 levels, but no luck:
```{r embed-xaringan, echo=FALSE}
xaringanExtra::embed_xaringan(url = "../..decks/covid-vh-ke/nov2020.html", ratio = "4:3")
```