SoapUI - REST false content type with attachements

I'm using REST requests for functional testing. One of my use case is sending attachement in POST requests. In the content type of sent data (watched in httplog console), there is "Content-Type: application/pdf; name=<NameOfTheDownloadedFile>"

Why content-type contain downloaded file name (i.e. name=<NameOfTheDownloadedFile>) ? REST style request are not designed to contain this kind of value.