(?: # begin header stuff, don't capture filenames, here,
# but instead wait for the --- and +++ lines.
(?:^diff\x20--git\x20$FN\x20$FN$LF)
(?: # begin header stuff, don't capture filenames, here,
# but instead wait for the --- and +++ lines.
(?:^diff\x20--git\x20$FN\x20$FN$LF)