Package for slackware 15 with slackbuilds.org 14.1 script
It's not an issue, in my case it's a kind of ... omission :) Making a package for Slackware 15 using xfce4-xkb-plugin.SlackBuild script and xfce4-xkb-plugin-0.8.3.tar.bz2 source, at line 91 of script (bellow "cp -a ") " AUTHORS COPYING ChangeLog INSTALL NEWS README ..." README file name must be replaced with README.md for a successful package build.
Happy coding.