xfce4-mcs-manager | Settings manager for Xfce4 | Mehr ...
This package contains xfce-mcs-manager, a tool that can be used to configure your Xfce4 desktop to meet your needs. Additionally, it contains xfce-setting-show which can give you a short and quick overview over your settings. If you intend to install Xfce4, you most probably want this package.
xfce4-mcs-manager-dev | Development files and static plugins | Mehr ...
This package contains the header-files and the static versions of the plugins for xfce-mcs-manager which is a configuration GUI for Xfce4 desktop environment. If you intend to develop applications which use the xfce-mcs-manager, you will have to install this package.