Some really interesting things.
c1,c2 and c3 are yellow and they are being set. What could they be? Globalvars, localvars? More likely localvars, they sound like something you'd name a temp variable. Very likely not macros because there's no point placing variables in macros for syntax highlighting anymore, because they have added more syntax highlighting as seen from the image. And considering the context they don't seem like variables put in macros either. They look very much like local variables.
Regular variables are purple, different from white equal signs. I'm assuming they added intellisense now.
Also notice how the scrProcessPlayer is not in another window. the window is divided into two.
Another thing to notice is the ".g" after scrProcessPlayer. Is it .gml? Could this imply that we can edit different files inside GM? Such as javascript code.
And the most obvious one, Create event is separate. So we can finally have events as only code.
The arrows next to the selected line are interesting too. are they just to make things prettier or would something happen if you clicked on them?