Yes this is correct.
In my understanding (because I am not a maintainer or developer on that
project) is that "Phoenix" is a working title for the current
unstable/testing version of wxPython. One of its feauteres is that it
will run with Python3.
But there are some ways to use wxPhoenix. What kind of system do you
work on? We can explain then how to build and install it.
You could try the wiki-pages, too. But they are inconsistent and
sometimes with confusing informations about the different possible build
processes.