appstream : Cross-distro effort for providing metadata for software in the Linux ecosystem ( https://www.freedesktop.org/wiki/Distributions/AppStream/ )
granite : Elementary OS library that extends GTK+ ( https://github.com/elementary/granite )
malcontent : Parental controls support library ( https://gitlab.freedesktop.org/pwithnall/malcontent )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a elementary
For Paludis use this rsync : rsync://gentoo.zugaina.org/elementary-portage
If you have a problem : ycarus(-at-)zugaina.org