This package uses dpatch in order to apply patches to the upstream 
source.
Patches are stored in debian/patches and their filenames usually end in 
.dpatch .
For further details, see the man pages for dpatch and dpatch-edit-patch.

All commands described below should be run from the top directory of the 
package source tree, unless otherwise stated.

 * To generate the fully patched source, in a form ready for
   editing, that would be built to create Debian packages, run: 

     dpatch apply-all

   Note: This should happen automatically when you run 
   dpkg-source -x on a dpatch source package.

 * To modify the source and save those modifications so that
   they will be applied when building the package, pick a
   suitably informative patch file name, for example
   01_add_README.source_file.dpatch, and then run:

     dpatch-edit-patch 01_add_README.source_file.dpatch

   This will place you in a new shell in a temporary copy of the 
   source tree.  Make your desired modifications to it, and then 
   exit the shell to create the patch file containing them (this 
   file will appear in debian/patches).

 * To remove source modifications that are currently being
   applied when building the package, run:

     dpatch unapply-all