There is a need to support the 'viewable' equivalent of items from source
systems, and possibly inside openEHR systems. The viewable equivalent from
a source system may be the only form available - e.g. a typical text (often
tab-indented) document representing a lab report (e.g. histology report). It
may have been processed into structured form as well, but there are usually
legal and / or clinical requirements to retain and make available the
viewable form. The viewable form is of no use for computing, only for human
viewing, attestation etc.

The viewable form should be considered a 'document', so should be available
only at the Composition level in openEHR (which is the document equivalent).
This feature could also be used to contain CDA documents.

Sometimes that whole document will be in another form and may need to be
retained as the document itself (or at least as a viewable form). Examples
might be text, rtf, doc, pdf, jpeg, gif and even CDA in the future.
A special case of this is when a document is added to the EHR by scanning and
there is no effort at OCR.