Which SCMs support "keep backups on destructive operations"?

[Daniel Serodio]

In SourceTree Help, the help for "Preferences: General" says the following about the Keep backups on destructive operations option:

If supported by the underlying system, whether to keep backup files when performing destructive operations like 'revert'.

My question is: is it Mercurial or Git that support these backups?

[stevestreeting · Accepted solution]

At the moment only Mercurial implements this, keeping '.orig' files on revert.

[Daniel Serodio]

Thanks, please consider adding this information to the Sourcetree's Help