I’ve just pushed some changes to the Ember client which makes it conform to the XDG Basedir spec.
The main difference is that the ~/.ember directory isn’t used anymore. Instead configuration files are put in ~/.config/ember while data files are put in ~/.local/share/ember.
During startup the contents of ~/.ember will be migrated, and a backup will be made in ~/.emberlegacy.
Many thanks to Olek Wojnar for making the bulk of the changes.