How to type in the redundant symbols in Simplified Chinese keyboard layout on MacBook?
The two sets of symbols are supposed to reflect how the keyboard behaves differently when the input source is set to Simplified Chinese Pinyin and when it is switched back to US via Caps Lock.

Even without the new keyboard, Pinyin input should work that way in Sierra, where the [ ] keys, for example, now produce 【 】.

The new keyboard is also available in the US online store.