Where does SQL Server restore backup from if I select Database as the source?

Question

When I restore an SQL server database from backup, I usually do it from a .bak file on the disk. There is also an option to restore from Database as a source - see this picture

Is this backup restored from the database log file?

Answer 1

It's from existing backups from databases that have been created on the server. It's essentially a list of all databases that have at least one recorded backup in the msdb database.

Source: MSDN

Select the database to restore from the drop-down list. The list contains only databases that have been backed up according to the msdb backup history.