When it's not runtime specific, libgdx typically is the first to get fixed/patched/changed.
The commit will have a label like [libgdx] Fix bone rotation. Then we port it to the other runtimes.
Like when I apply it to spine-csharp, we've agreed to name it [csharp] Fix bone rotation and link to the libgdx commit it was based on.
Other times, we do a bunch together and label it accordingly, but still link to the original commit.
Typically, nothing in the dev branch gets applied to the other runtimes in master. We only start porting when dev merges to master. This is particularly true when it involves major changes. The new AnimationState changes are a huge change that also involves the Animation class and Timeline classes. So you won't see that in master for a while.
Almost there though. Personally, I'm super excited. I've been answering questions about these missing features since I could remember.
If it's a big runtime update resulting from an editor update, the changes in libgdx typically get squashed together under a Spine version label when ported. "Updated to Spine 3.5" or something. That just means all the changes and fixes applied when developing 3.5 were included when porting.
Regarding the AnimationState changes, if it's not part of 3.5 (it might not, since it has nothing to do with Spine editor), it'll probably have its own commit, but all the AnimationState changes squashed together rather than per item.
