A few months ago I happened to install Debian/unstable on a G4 mini. ppc32 is no longer a supported architecture -- purely "what you get is what you get".
Still, the process was mostly painless. Everything I needed worked out of the box.
This is the exact same transition process 68k went through for most platforms it was on. Just left it in the build process and as packages were unable to be built for the arch they just delisted them from the builder until core packages no longer functioned; at which point total support was removed:
Still, the process was mostly painless. Everything I needed worked out of the box.