Package whohas

http://www.philippwesche.org/200811/whohas/intro.html

whohas is a command line tool that allows querying several package
lists at once - currently supported are Arch, Debian, Gentoo and
Slackware. whohas is written in Perl and was designed to help
package maintainers find ebuilds, pkgbuilds and similar package
definitions from other distributions to learn from.

Version: 0.29.1