Studying to prior versions

• The (unofficial) cran organization on GitHub where each commit represents a CRAN release:
  • https://github.com/cran/usethis/commits/HEAD

• Prior CRAN package bundles (.tar.gz files):
  • https://cran.r-project.org/src/contrib/Archive/usethis/

• The repository where usethis is actually developed:
  • https://github.com/r-lib/usethis/commits/HEAD