yurikoles [1] filed a request to merge virtualbox-modules-mainline [2] into virtualbox-svn [3]:
Not updates for 3.5 years. I think users of linux-mainline will benefit from bleeding-edge virtualbox. [1] https://aur.archlinux.org/account/yurikoles/ [2] https://aur.archlinux.org/pkgbase/virtualbox-modules-mainline/ [3] https://aur.archlinux.org/pkgbase/virtualbox-svn/
