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

Files: data/fmcstest.rda
Documented: man/fmcstest.Rd
  Sample compound structures stored in SDF format. \usage{data(fmcstest)

 -- Andreas Tille <tille@debian.org>  Mon, 23 Mar 2020 21:25:57 +0100
