What is a rtfd file and how do I open a rtfd file?
RTFD files are text documents that provide support for attachments containing PDFs, other files and documents or images. These text documents in the RTFD extension essentially have the same support and features of RTF documents, but are commonly known as Rich Text Document Directory files. Initially, RTFD format technology was developed for NeXT OS versions, and today, Mac OS X provides more support for these RTFD files. In Mac OS X, users can open and view the content attached to these RTFD files by selecting "Show Package Contents" in the right-click menu, and these attachments are mostly other files added to an RTF document.
Relevant rtfd file links:How to open rtfd file on Youtube
How to open rtfd file on Wikipedia
How to open rtfd file on Microsoft.com