the x11-misc/gtkdialog ebuild still uses the google repository. Is there a new home of the project or a fork? The very old source ships with a long list of QA warnings.
The automatic mirror to github seems to be dead, all issues on stall https://github.com/oshazard/gtkdialog/issues xfce-extra/xfce4-composite-editor-0-r1 is the only reverse dependency
commit 1af51fa380eec5b1e845c26eb9475ca0b73bb9dd Author: Jeroen Roovers <jer@gentoo.org> Date: Sat Jul 28 14:07:59 2018 +0200 x11-misc/gtkdialog: Add live ebuild. Package-Manager: Portage-2.3.43, Repoman-2.3.10