Was a pain in the butt to free up the ~40 MB of rootfs necessary to do the package install (uninstalled everything from extras-testing/devel and still needed to resort to symlink magic to make it go), but ...

It works! Having a back button in browser portrait mode is great, finally frees up the "long press" of the camera softkey for bigger and better things.

I did find a minor regression -- doing ctrl+backspace (via shortcutd) when in browser portrait bounces you back to the desktop rather than the application dashboard. ..it's not the end of the world, I can press the button again.