arts, you need to add a forward slash and asterisk after PART, within the parentheses.

---
name: toc-appendix

# Appendix

.pull-left[
`index.Rmd`

```r
# Prerequisites {-}
```
`01-intro.Rmd`

```r
# (PART\*) Act one {-}

# Introduction
```


...

`05-summary.Rmd`

```r
*# (APPENDIX) Other stuff {-}

# Final Words
```

]

.pull-right[
.center[
&lt;img src="img/bookdown-skeleton-toc_appendix.png" width="65%" /&gt;
]
]

??? 

We can also add an appendix, which by default is an unnumbered part.

The numbering