RE: Changes for emacs 28

[Drew Adams]

> > Beside this, we could create a kind of hierarchical configuration
> > system, where the hierarchy is not (like is the case in Custom) based
> > only on functionality, but rather on "popularity/importance/frequency".
> 
> It would also be good to be able to be able to present options in a
> logical and predetermined order in custom instead of the current
> alphabetical order.  Could custom be extended to handle that?  Maybe we
> could add a :weight property to defcustom?

Isn't that what :group is about?  An author can assign
any option or face to any number of :groups.

A :group is thus like a Delicious-style tag, in a way.

https://en.wikipedia.org/wiki/Delicious_(website)

Finder keywords, that is, keywords in a `Keywords'
file-header field, are also like tags in this way.

`customize-group' and `finder-by-keyword' are UI
entry points.  They could be improved.

Uses of finder keywords haven't been too systematic
so far.  And :group has been used sparingly so far.

But both seem to have this property that you can
assign multiple such "tags" to a thing (file/library
for finder keywords, option/face for :groups).

An advantage of organization by such tags is that
there can be any number of "logical and predetermined
orders".  Or rather, tags define sets, which are
unordered, but there can be hierarchies of sets.  And
the sets - their hierarchies and their elements - are
easily updated/redefined.