"local" setting in remote-ftp package


Hi all,
I have a question about the remote-ftp package that I wonder if anyone can shed light on.
I noticed that when creating a new .ftpconfig file automatically via one of the commands [Create FTP Config or Create SFTP Config], one of the default generated settings is “local” (with an empty string for default value). I cannot seem to find a description of what this setting does anywhere!
I was hoping it might be a way to specify a subset of the project to use for uploading, but that didn’t seem to be the case… Has anyone figured this out?