I've heard of passive ftp but this is new to me. I searched the Web for
'passive sftp' and got 32 hits total of which only a few applied and
none of which explained anything.

Is there such a thing? If so, what are it's features and
characteristics? The comment came from a vendor in the context of
"keeps sftp from prompting for a password" which I had associated with
user keys. Is the vendor confused or do they know something I don't?

Thanks for any and all replies.