Wow must say after using atlassian products for several years it is about time for an upgrade. You can see more here.
Interesting they decided to go for react on their UI's, i wonder if they will upgrade their UI's to be more single page designs or keep it as full gets for every request. You can find out more here about atlaskit their react UI library.
So far on their bitbucket things are looking quite active. Been meaning to write a plugin or 2 for confluence. When I start with that I will definitely post updates here.