
The directory /usr/etc is an optional directory and used by Fedora, RHEL 9, and openSUSE. The purpose of /usr/etc is to store distribution-provided configuration files that can be overridden by user-modified files in /etc. /usr/etc is not in FHS. However, as Torsten stated in his comment (https://github.com/thkukuk/atomic-updates_and_etc/issues/2#issuecomment-524848666) "[FHS] is currently nearly as dead as LSB, we can only ignore it if we don't want to stop and kill all innovation."