Too many packages describing essentially the same (what HAL used to do
before):

- Device (auto)discovery (HAL did this...)
- Storage support (udisks or gvfs -> udev[extras]) (HAL did this...)
- Power support (upower -> udev[extras]) (HAL did this...)
- Installs rules (Same as installing HAL fdi file, more or less...)

So the description could be:

"Enable udev support (rules install, device discovery, power and storage
device support, etc)"

17 packages:

app-emulation/libvirt:udev - Use sys-fs/udev to determine available devices
app-misc/emelfm2:udev - Enable udev support using sys-fs/udisks
dev-libs/cyberjack:udev - Enable installation of udev rules
gnome-base/gvfs:udev - Enable udev base replacement code for cdda feature
media-libs/libgpod:udev - Enable udev support
media-sound/pulseaudio:udev - Use sys-fs/udev for autodiscovery of
sound devices; this replaces the deprecated sys-apps/hal autodiscovery
code.
media-sound/rhythmbox:udev - Enable hardware detection via sys-fs/udev
replacing the deprecated sys-apps/hal code.
media-video/gxine:udev - Use sys-fs/udev for autodiscovery of devices;
this replaces the deprecated sys-apps/hal autodiscovery code.
media-video/vlc:udev - Enables Linux udev services discovery.
net-misc/connman:udev - Enable udev support.
net-misc/ofono:udev - Use sys-fs/udev for modem detection.
sys-cluster/drbd:udev - Enable udev integration
sys-fs/ntfs3g:udev - Install udev rule to make udisks use ntfs-3g
instead of the kernel NTFS driver.
x11-base/xorg-server:udev - Enable devices discovery via udev
x11-libs/libfm:udev - Use sys-fs/udev to determine available devices
x11-misc/pcmanfm:udev - Use sys-fs/udev to determine available devices
xfce-base/thunar:udev - Enable udev support (required by
xfce-extra/thunar-volman)