Comment by jasona123

Welp, (part) answered my own question:

Translated from Japanese from the announcement^:

Q. Today is October 1st, isn't it?

A. Yes, today is October 1st!

Q. What is the significance of today?

A. When we were considering the perfect day to announce the keyboard, we noticed the widespread use of the "101-key keyboard"—a type featuring 101 keys. So, we decided to launch it on October 1st as a nod to that standard.

^ https://blog.google/intl/ja-jp/products/android-chrome-play/...