The semantics of plugging in (ODF all versions)

Dear ODFers,

In 9.4.7.1 the <draw:plugin> element is described.

----b
The <draw:plugin> element represents a binary object (plugin) that is
plugged into a document to represent a media-type that usually is not
handled natively by office application software.
----e

* 'plugins' are never defined in the spec. What exactly are they?

* HOW is a plugin 'represent[ed] as a binary object' ?

* by what mechanisms can a 'plugin' interact with an ODF document and
its hosting application?

* Any security model?

* Any limits on plugin behaviour? (conformance implications?)

* how is a plugin (as the spec says) 'plugged in'? (i.e. what are the
semantics of plugging in ODF?)

* how can a user/implementer determine whether a media type is of the
class "usually [...] not handled natively by office application
software" ?

A couple of vague lines of description are totally inadequate for what
looks like a major feature of the spec.

And yet again, a formal Terms & Definitions section might help to get
some of the vocabulary in ODF under control.

- Alex.