In ephemeral mode, profile data is saved on disk only for the length of the user session. Features like browser history, extensions and their data, web data like cookies, and web databases aren't saved after the browser is closed. This doesn't prevent a user from manually downloading any data to disk, or from saving pages or printing them. If the user has enabled sync, all data is preserved in their sync accounts just like with regular profiles. Users can also use InPrivate browsing in ephemeral mode unless you explicitly disable this.