We tried to delete a confluence space, but when my friend pressed "delete space" they were promptly sent to a different space. Then they clicked "delete this space" at confirmation page and only then I noticed, that we're in a different space. Another name, another icon. Somehow, delete button sent from a freshly created space into an old one with a bunch of work data.
While not having a backup is a tragic oversight, this situation became possible due to a bug, as they were pressing "delete space", while being in a different one.
I don't know how to prove or demonstrate this bug, as I couldn't reproduce it on this account and we didn't record our video conference. Please, find it and fix it for other people in the future.
If you know, how to restore a space without backup, please tell.
P.S. Maybe make mandatory XML backups on deletion, or store them for a while longer before actual deletion happens.