Implement tiny biome distribution

docs/PORTING.md

@@ -340,6 +340,11 @@ Age-seeded biomes in Legacy's diagonal checkerboard layout. Each cell is one
 16-by-16-block chunk, and the built-in serializable biome source reconstructs
 the same layout whenever the Age reloads.
 
+Version 0.2.24.0 applies Tiny Biome Distribution using three deterministic
+Age-seeded biomes and softly bounded seeded regions. Tiny begins at Legacy's
+smallest 16-block nominal scale; the serializable biome source retains its
+seed, selected biomes, and scale across Age reloads.
+
 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