The template located at the url "$confprefix/setup/setup-restore.action?synchronous=false" for a given confluence installation provides a full directory path to the "backup" folder location which may real information regarding the location of the confluence data directory on the file-system. This is not a real problem in itself, but could be used in combination with another vulnerability within confluence at a later point.

Also, if there are any backup files in the backup folder - the names of the file(s) will also be "leaked".