On Feb 16, 2023, at 17:10, Eli Zaretskii <eliz@gnu.org> wrote:

Did you try looking at Git history for this code?  Maybe the log
messages of the relevant commits and/or bug reports and/or discussions
on emacs-devel around the dates of the commits tell something about
the reasons?  I've seen too many cases where changing old code
introduced regressions because some aspect of the behavior was
disregarded, and would like to avoid that, certainly if this is for
the release branch.