At the end of Shiro Sagisu's Robe Des Champs (KK_A09_miyagi), there is a dotted X with brackets covering two bars.
Just look a bit further on the page: right below that staff there are two footnotes with the same symbol:
As the comment from 小太郎 explains, the
※ symbol is a reference mark used in Chinese, Japanese and Korean writing. This is clearly the case, since the published score was mainly intended for Japanese market.
The second footnote can be translated as:
These two measures are not played on the CD
It means that they probably existed in the original written score (and are probably played at some point in the anime), but they omitted them when recording the CD.
Here is the official recording, which doesn't include those two bars, exactly as the note indicates (the section starts around 1'08"):
It's an optional part that you may or may not play before returning to the beginning.
Whether you do it or not only depends your personal taste.
: there is no absolute standard for reference symbols in music notation: for Western published music, the common one is the asterisk, but numbers or other symbols are also used (like ♦ or ♠), normally enclosed within square brackets (exactly like this note ;-) ); publishers may use their own standards, especially for cases involving complex annotations or multiple footnotes, which is common in critical editions (Barenreiter, Ricordi, etc.).