套件：r-cran-backports（1.5.0-2） [debports]
reimplementation of functions introduced since R-3.0.0
Implementations of functions which have been introduced in R since version 3.0.0. The backports are conditionally exported which results in R resolving the function names to the version shipped with R (if available) and uses the implemented backports as fallback. This way package developers can make use of the new functions without worrying about the minimum required R version.