select which kind of blanks should be visualized, for example, trailing blanks,
leading blanks, spaces, tabs, newlines, etc.
+** xesam.el is an implementation of Xesam, an interface to (desktop)
+search engines like Beagle, Strigi, and Tracker. The Xesam API
+requires D-Bus for communication.
+
** zeroconf.el offers service discovery and service publishing
interfaces according to the zeroconf specification. It communicates
with Avahi, a zeroconf implementation, via D-Bus messages on systems