What does the icon before Local Branches mean in Android Studio 3.3.1?

Question

I find that there are two icons before both newCW and master Local Branches, what does these icon mean?

And more, none icon before other Local Bran

Answer 1

The star icon next to the master branch means that it is marked as a favorite branch. This is a default behavior from IntelliJ. (source)

The icon next to the newCW is the HEAD icon. It means that this is the branch you are working on.
I haven't found an explicit description of this in the docs, but you can see it here. It's almost the same icon for tags, just not the same color (see here).

Because Android Studio is built on top of IntelliJ, don't hesitate to look at IntelliJ documentation for IDE relative questions.