Explanation for binary files inside source package according to
  http://lists.debian.org/debian-devel/2013/09/msg00332.html

This package contains several example data sets

Files: vignettes/bfst1.rda
       vignettes/bfst2.rda
Documentation: vignettes/bfst.Rnw
  Data files for vignette

Files: vignettes/morph1.rda
       vignettes/morph2.rda
Documentation: vignettes/morph.Rnw
  Data files for vignette
