I'm using Rmarkdown to make a blogdown post, and I'm hoping to implement something I saw in Hadley Wickham's Advanced R online book, which is a footnote link that when clicked on opens as a tooltip instead of in the footer of the page. See image below for an example.
I have no idea how he did this and I couldn't find any options in the source code that reference footnotes or tooltips. In the source for this page, the footnote is just a regular footnote (no special packages appear to be used). Thank you for your help!
