Everything about an R package when you want to learn how to develop an R package. Specifically, it has examples for

• DESCRIPTION
• roxygen documentation
• namespace
• S3 generic functions
• C code
• datasets
• demos
• R Markdown vignettes

Forget about package.skeleton(); you will regret learning that "official" function one day. The Rd documentation, NAMESPACE and the Collate field in DESCRIPTION are automatically generated by roxygen2. This is how I generated them:

library(Rd2roxygen)
rab('rmini')

Well, that is not what I really did. I just open rmini.Rproj in RStudio, and click the button Build & Reload, which basically runs the code above.