betterbird-bin : Betterbird is a fine-tuned version of Mozilla Thunderbird. ( https://github.com/Betterbird/thunderbird-patches/ https://betterbird.eu/ )
mailspring-bin : A beautiful, fast and fully open source mail client for Mac, Windows and Linux ( https://getmailspring.com/ )
proton-mail-bin : Beta Client for Proton Mail ( https://proton.me/mail )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a guru
For Paludis use this rsync : rsync://gentoo.zugaina.org/guru-portage
If you have a problem : ycarus(-at-)zugaina.org