Bulk LBMs (#14954)

doc/lua_api.md

@@ -5522,6 +5522,8 @@ Utilities
       override_item_remove_fields = true,
       -- The predefined hotbar is a Lua HUD element of type `hotbar` (5.10.0)
       hotbar_hud_element = true,
+      -- Bulk LBM support (5.10.0)
+      bulk_lbms = true,
   }
   ```
 
@@ -9124,7 +9126,12 @@ Used by `minetest.register_lbm`.
 
 A loading block modifier (LBM) is used to define a function that is called for
 specific nodes (defined by `nodenames`) when a mapblock which contains such nodes
-gets activated (not loaded!)
+gets activated (not loaded!).
+
+Note: LBMs operate on a "snapshot" of node positions taken once before they are triggered.
+That means if an LBM callback adds a node, it won't be taken into account.
+However the engine guarantees that when the callback is called that all given position(s)
+contain a matching node.
 
 ```lua
 {
@@ -9148,7 +9155,13 @@ gets activated (not loaded!)
     action = function(pos, node, dtime_s) end,
     -- Function triggered for each qualifying node.
     -- `dtime_s` is the in-game time (in seconds) elapsed since the block
-    -- was last active
+    -- was last active.
+
+    bulk_action = function(pos_list, dtime_s) end,
+    -- Function triggered with a list of all applicable node positions at once.
+    -- This can be provided as an alternative to `action` (not both).
+    -- Available since `minetest.features.bulk_lbms` (5.10.0)
+    -- `dtime_s`: as above
 }
 ```