Port dry Cave Ages and safe landing to 26.3 beta

docs/MINECRAFT_26_3_PORT.md

@@ -495,6 +495,19 @@ accepts the existing authored distribution pages for those terrains. New Flat
 chunks can vary vegetation by biome; Void keeps biome climate without adding
 a floor or decorations. These are beta-port slices, not full 1.21.1 parity.
 
+The local `1.0.1.37-beta.1` slice ports Cave terrain authoring using the
+26.3 caves noise preset. Cave and Nether Biome pages can be distributed
+through an Age, and travel searches for footing from Y=64 downward rather
+than mistaking the cave roof for the surface. Nether-style cave material
+replacement from 1.21.1 remains a separate port task. The local
+`1.0.1.38-beta.1` follow-up
+keeps Cave Ages dry by default: the vanilla 26.3 Cave preset otherwise fills
+low openings with water. This changes newly generated chunks only; a future
+Flooded page will deliberately set an authored water level in both maintained
+versions.
+The local `1.0.1.39-beta.1` follow-up makes the 26.3 landing search reject
+fluid at feet and head height and prevents a submerged fallback platform.
+
 ## Verification of this first slice
 
 The 1.21.1 `compileJava` and `build` tasks passed offline after the backend