VEP-007 update

[Markus Demleitner]

Dear Colleagues,

As noted in
http://mail.ivoa.net/pipermail/semantics/2021-September/002846.html,
VEP-007 (#documentation in datalink/core) exposed a problem with
#documentation's definition.  It currently explicitly requires
human-readability:

  Extra information on the item in human-readable text form, ranging
  from processing logs to weather reports to technical documents on
  instruments to related publications.

It turns out that "human-readability" is hard to define.  Is a FITS
header human-readable?  Or a PDF label?  Or... a PDF?  Frankly, if
all I have is a text editor, I'll go for the FITS header rather than
the PDF.  On the other hand, there are few things that are
human-unreadable if given the appropriate tools.

Hence, I'd say the "human-readable" ought to be taken out of the
definition as not reproducible between indviduals, and also not
useful in practice; I'm quite sure that I'd be cross with the
publishers if they had a detached PDF label but wouldn't show it
under #documentation.

I have amended VEP-007 accordingly
(https://volute.g-vo.org/svn/trunk/projects/semantics/veps/VEP-007.txt)
to change documentation's definition to:

  Structured or unstructured metadata helping to understand, 
  interpret, or work with #this.  Such information can range from
  processing logs to weather reports to technical documents on
  instruments to related publications.

The part on "structured or unstructured" caters (or so I hope)
towards François' concerns from
http://mail.ivoa.net/pipermail/semantics/2021-September/002844.html,
where once we have further terms talking about explicitly
computer-readable ("structured") metadata and we find we have to
enable common behaviour among them, the introduction of, say,
*#structured-metadata will not come as a surprise.

Can everyone live with this?  Do you perhaps have suggestions for how
to make this more precise?

Thanks,

             Markus