Very weird. They provide a very specific future date for this, and avoided using the term "open source". I can't recall any other company doing this. Most of the time, companies provide a github repository at the same time they make such announcements. Even for twitter, Elon Musk promised the algorithm would be opened, and then some time later it was just there. While generally it is a positive thing to see code being available, I wouldn't think too much into it until I can see the license and the code.