Answer
The “Upload Data” in the True Content Type content processor relates to all data uploaded using HTML forms, mime-type: application/www-form-encoded.
This specific mime type is common for uploaded data sent via HTML, for example, if you want to upload an EXE file using Webmail account (e.g. Gmail), Gmail will encode the EXE file with the "www-form-encoded" structure. The Finjan will open the encoded file and scan the real file inside.