It's for your follows (changed from check mark to shield).
A timeline of changes in case you want
Discussion
Lol. I see colored lines and interpret this as "stuff happened"
Oops - thought it would be helpful 😂
In any case, 61 to 66 is a big leap
Global feed is gone - it's now just another list on top bar of Home & everything Derek mentioned
Global is still there, you select which List to view from the drop down box. Make custom lists and they'll show up there too, and you can flip between them