Functions introduced or changed since R v3.0.0 are re-implemented in
this package. The backports are conditionally exported in order to let
R resolve the function name to either the implemented backport, or the
respective base version, if available. Package developers can make use
of new functions or arguments by selectively importing specific
backports to support older installations.

Homepage:
https://CRAN.R-project.org/package=backports
