Apply End and Nether biome materials

docs/PORTING.md

@@ -350,6 +350,11 @@ Large, and Huge reuse Tiny's seeded, softly bounded regions at nominal widths
 of 32, 64, 128, and 256 blocks. Every size selects three deterministic biomes
 and serializes the selection, Age seed, and scale with the runtime dimension.
 
+Version 0.2.25.1 applies biome-specific material rules without replacing an
+Age's selected terrain profile. End biome columns generate from End stone;
+Nether biome columns use Minecraft's Nether surface rules for netherrack,
+soul sand, basalt, and nylium instead of inheriting Overworld blocks.
+
 Version 0.2.14.0 restores the legacy Linking and Descriptive Book artwork for
 inventory items and gives each book its matching open-book texture when placed
 on a Book Stand. Return Linking Books created inside another Age also retain and