>>517
試したけど俺の環境では↓こうなるよ
diffだけなら十分実用レベル

$git diff
diff --git a/book.xlsx b/book.xlsx
index c75fc9a..6215aa2 100644
--- a/book.xlsx
+++ b/book.xlsx
@@ -1,5 +1,6 @@
Sheet1
Hello
+ OOXML
World