Hi @Jiangming He ,
According to [2.1.720 Part 1 Section 18.8.45, xf (Format)] in MS-OI29500]1, "The default value for applyBorder in cellStyleXfs is true.", so applyBorder is not required, but defaults to true.
For applyNumFmt, I believe the attribute you're referring to is applyNumberFormat. If this is incorrect, please let me know. For applyNumberFormat, also from [2.1.720 Part 1 Section 18.8.45, xf (Format)] in MS-OI29500]1 "The default value for applyNumberFormat in cellXfs element is false.", so applyNumberFormat is not required, but defaults to false.
Please let me know if this answers your question.
Best,
-Mike