I should also mention that HarfBuzz is disabled in this build, so there is no RTL support.
The Back button works for me sometimes as expected, but not always.
@jk
back button indeed was not always working as expected, for instance in settings submenus I expected to go back to the previous menu, rather than closing settings altogether.
Another little detail that I forgot to mention: this has been built with min API level 19, so Android 4.4 or later is the requirement.