window manager configuration file question

[jb_daefo]

After updating the window manager to a new version I noticed its configuration file(s) were not locally updated, and due to sparse online or man page information am unable to figure out how to know which "new" feature made features in a theme file not appear onscreen.

example text line
</Group>
<Group>
<Name>xcalc</Name>
170-odd lines of the above...

Keymaps, modes, paths, styles....

The port installs
A file(s) in /usr/local/etc

And then the user optionally...
A file in the user's home directory
A subdir in the " " " with the theme within.


As the theme is working but several years old, is there any typical way
to test the old conf and adding in the new conf section by section to see
what works and what breaks?
Just in case anyone has done it before. Not wanting to waste anyone's time...
It would take me hours and hours.... similar to reconciling all the
make.conf [1] I have with revision filename-extensions that cannot be
"standardized" without multi-terminal-window editing, as it is much easier
to simply add/remove lines from the latest make.conf as need be...

[1] I had thought that
make.conf-gcc
make.conf-clang
make.conf-developer
etc could be maintained upto date easily, but was wrong... not enough
time, simply.