Hidden Commits in 4.3

[Jun Wu]

Excerpts from Pierre-Yves David's message of 2017-04-05 13:06:04 +0200:
> I think we really needs to take a step back here. Before thinking about 
> unification, I think we needs a clean definition of what we are doing 
> here. As mentioned in another thread[2], they are at least three 
> identified categories of things we want to hide. obsolete, internal, and 
> some local only hiding. The first two are quite well defined now, the 
> last one less so.

Why it has to be 3 categories of hiddenness? You explained how 3 categories
work. Maybe I missed something, but I cannot find proof about why a unified
single category does not work. I also failed to find other people supporting
the 3 categories idea. If it is for some rare cases that are not useful in
common workflows, I wonder whether it is worth the additional code and
concept complexity (comparing with a single unified hidden category).