Jython defaults to Editline but does not depend on it

The jython startup script at /usr/bin/jython
default

python.console.readlinelib=Editline

but does not depend on an editline package. This looks like a bug.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: jython 2.5.2-2
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Thu Dec 5 15:47:15 2013
InstallationDate: Installed on 2013-09-10 (86 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: jython
UpgradeStatus: Upgraded to saucy on 2013-10-23 (42 days ago)