alien does not support data.tar.xz
A program that converts that converts between linux packages
Brought to you by:
kyleb000
newest deb packages uses data.tar.xz (instead tar.gz)
see post about it
https://sourceforge.net/p/alien-pkg-convert/discussion/general/thread/d5eabd61/?limit=25#cd4f
just install dpkg package to use dpkg-deb -x for unpacking