Status of Extended XLinks (1:n Relationships)?

Hi list,

as you already know, DocBook 5 allows extended XLinks[1] which you can do some 
fancy things with it. ;)

As I was interested in the use case of creating 1:n link relationships (and 
still be), I started a thread some years ago [2]. I got some very helpful 
ideas and Bob wanted to bring this to the attention of Docbook's TC and "if 
they have any thoughts on it".

Is there any progress on this topic?

Probably I missed some related discussion, but... is there already something 
"official"? I haven't seen anything related in The Definitive Guide (TDG). But 
I believe, it would be very helpful to have some guidelines how to do this, 
documented in TDG.

Also in the light of assemblies, topics etc. this becomes more important to 
have an official blessed method how to express it.

IMHO what I see from the outside, the following issues are needed to really 
support extended XLinks:

1. Decide on a markup how to express 1:n relationships
   I've found a post from Norman[3], this may be a good start (or my original
   thread[2} from 2013).

2. Support extended XLinks in the stylesheets

3. Document it in DocBook's TDG


How difficult would it be? What are the pros and cons? Does it help to open an 
issue in GitHub? What else is needed...?

What do you think? :)


-------- References
[1] http://tdg.docbook.org/tdg/5.2/extendedlink.html
[2] https://lists.oasis-open.org/archives/docbook/201307/msg00015.html
[3] http://markmail.org/message/deiehzkvwmh6c2zp?q=xlink+list:org%2Eoasis-open
%2Elists%2Edocbook-tc

-- 
Gruß/Regards
  Thomas Schraitle