The source material for the Tachyon Debian package was originally designed with
multi source tarballs in mind [1,2]. Unfortunately, at the time of packaging,
this feature is not supported by git-buildpacckage (#561071), therefore an ad hoc
has to be figured out:
1] the upstream source tarball was downloaded and then repacked throught a standard
   uscan/watch machinery to obtain `tachyon-0.99~b6+ds.orig.tar.zx' (for details,
	 see `debian/{rules, watch,repack});
2] the second source tarball that contains missing sample material grabbed from the
   internet by hand (see `debian/copyright' for furhter information) was created
	 wrt the multi source scheme and named `tachyon_0.99~b6+ds.orig-pkgextra.tar.xz';
3] the second source tarball `tachyon_0.99~b6+ds.orig-pkgextra.tar.xz' was added by
   hand to the repacked source tarball `tachyon-0.99~b6+ds.orig.tar.zx' to get
	 the standalone source tarball `tachyon-0.99~b6+dsx.orig.tar.zx', the missing
	 sample material being gathered into the folder `pkgextra'.

[1] http://raphaelhertzog.com/2010/09/07/how-to-use-multiple-upstream-tarballs-in-debian-source-packages/
[2] https://packages.debian.org/source/sid/spamassassin
