Because powerline depends on python-powerline (the python2 version) and recommends python3-powerline (python3) so both end up getting installed.
$ apt-cache show powerline Package: powerline Architecture: amd64 Version: 2.6-1 Priority: optional Section: universe/python Origin: Ubuntu Maintainer: Ubuntu Developers <ubuntu-devel-disc...@lists.ubuntu.com> Original-Maintainer: Jerome Charaoui <jer...@riseup.net> Bugs: https://bugs.launchpad.net/ubuntu/+filebug Installed-Size: 251 Depends: python:any (>= 2.7.5-5~), python-powerline Recommends: fonts-powerline, python3-powerline ... -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1575802 Title: default dependancy should be python3-powerline To manage notifications about this bug go to: https://bugs.launchpad.net/hundredpapercuts/+bug/1575802/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs