New dependency needed as of Aug 10 Beta update (now needed for stable)
libibus
is now needed for steam-native to render the library and other screens in the steam client interface. I can confirm that installing this dependency restores client to normal functionality.
(Without this dependency, it simply shows a black screen for Library/Store/etc, and doesn't show friends list or messages at all)
Arch bug report: https://bugs.archlinux.org/task/75600
steam-for-linux bug report: https://github.com/ValveSoftware/steam-for-linux/issues/8756