Debian Stretchの通知デーモンの「provider」フィールドは何ですか？

「サプライヤー」フィールドとは何ですか？Debian Stretchの通知デーモン？

仮想パッケージを意味しますか？

でもそうだDebian Stretchの通知デーモンは仮想パッケージではありません。特定のファイルのリスト

$ aptitude show notification-daemon
Package: notification-daemon             
Version: 3.20.0-1+b1
State: installed
Automatically installed: yes
Priority: optional
Section: x11
Maintainer: Debian GNOME Maintainers <[email protected]>
Architecture: i386
Uncompressed Size: 398 k
Depends: libatk1.0-0 (>= 1.12.4), libc6 (>= 2.4), libcairo2 (>= 1.10.0), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.37.3), libgtk-3-0 (>= 3.19.12), libpango-1.0-0 (>=
         1.14.0), libx11-6
Provided by: cinnamon (3.2.7-4), dunst (1.1.0-2+b1), gnome-flashback (3.22.0-3), gnome-shell (3.22.3-3), lxqt-notificationd (0.11.1-1), mate-notification-daemon (1.16.1-1),
             mate-notification-daemon (1.18.1-1~bpo9+1), notify-osd (0.9.35+15.04.20150126-1+b1), plasma-workspace (4:5.8.6-2.1+deb9u1), python-jarabe (0.110.0-3), xfce4-notifyd
             (0.3.4-1)
Description: daemon for displaying passive pop-up notifications
 notification-daemon displays passive pop-up notifications, as per the Desktop Notifications Specification. 

 The Desktop Notifications Specification provides a standard way of doing passive pop-up notifications on the Linux desktop. These are designed to notify the user of something
 without interrupting their work with a dialog box that they must close.  Passive popups can automatically disappear after a short period of time.
Homepage: https://git.gnome.org/browse/notification-daemon/
Tags: implemented-in::c, interface::daemon, interface::graphical, interface::x11, role::program, uitoolkit::gtk, use::monitor, x11::applet, x11::application