cran_usage.Rmd is a parameterized RMarkdown report which tabulates data on function usage of a package's CRAN dependencies. It utilizes a local CRAN mirror and searches within the package tarballs for the data. On my machine the CRAN mirror currently takes ~ 6.7 Gb of space.
This information could be useful for package authors to determine how people are using their package on CRAN.
Some example reports: