This morning I uploaded last KDE Framework 5 packages to the [extra] repository in Arch Linux.
Since Beta 2, KF5 packages are co-installable with KDE 4 and for this reason those packages are built with the /usr prefix, not /opt/kf5 as previously on AUR.
The only exception here was kactivities: both versions (the KDE 4 version and the KDE Framework one) ship a kactivitymanagerd binary.
Thanks to Ivan Čukić tip both kactivities packages have been split between binary and libraries. In fact, Ivan told me KDE 4 needs kactivities 4.x libraries, but it works with kactivitymanagerd ship by kactivities from KDE Frameworks.
For this reason kactivities4 and kactivities-framework Arch Linux packages provide a kactivities virtual package which allows KDE 4 users to install KDE Framework 5 on the same system under /usr.
Plasma Next packages will (hopefully!) follow in the next days, but they will go in [kde-unstable] instead. Also, their prefix will be /opt/kf5 so they are co-installable.
pacman -S kf5 kf5-aids and enjoy KDE Frameworks libraries!
PS: KWin 5 is already in [kde-unstable]!
UPDATE: I’ve been asked several times now, so here are the instructions on how to run Plasma Next components, e.g. KWin 5:
# pacman -S kwin oxygen
$ export KF5=/opt/kf5
$ export QML2_IMPORT_PATH=$KF5/lib/qt/qml:/usr/lib/qt/qml
$ export QT_PLUGIN_PATH=$KF5/lib/qt/plugins:/usr/lib/qt/plugins
$ export XDG_CONFIG_DIRS=$KF5/etc/xdg:/etc/xdg
$ export PATH=$KF5/bin:$PATH
$ kwin --replace