Summary is "create mode ..." etc. and you can already enable/disable it.
That "N files +M/-N lines in total" is _not_ a summary; it is an integral
part of ascii-graphical --stat output, which is supposed to produce output
like "git diff -p | diffstat". We won't split it out of --stat without a
very good reason, there doesn't seem to be an option to "diffstat" for
such a thing, so...
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