In the case of database encryption (for example), whether and how that happens?
My understanding is that remains the domain and responsibility of each user to decide and implement.
That said, users may opt for say this https://mariadb.com/kb/en/library/data-at-rest-encryption-overview/
Note also this PR contribution that did not pass muster to merge into the core Are db backups sent to dropbox encrypted? - #6 by OneiricIT