Use emacs-29 or master branch to contribute mix of bug fixes and new features?

[Jens Schmidt]

Hi,

I'm planning for some changes in plstore.el, in the context of this thread:

  https://lists.gnu.org/archive/html/emacs-devel/2023-05/msg00327.html

Some of the changes go rather into the "cleanup" category (extending 
commentary, providing tests), some into "bug fix" category, and some 
into "new feature".

I will provide these as separate commits as far as easily possible, but 
at least I wanted to keep them on one branch while developing them. 
Where should I start that off: emacs-29 or master?

It probably does not matter much for plstore.el, which seems to be 
rather stable, but is there some general guideline for such "mixed type 
commits"?  The information in file CONTRIBUTE does not seem to mention 
this case.

Thanks

Jens