diff --git a/README.md b/README.md
index 3ff8fe8..1050cf0 100644
--- a/README.md
+++ b/README.md
@@ -53,3 +53,11 @@ This file contains a mapping of Minecraft string biome IDs to their legacy integ
 
 ## entity_identifiers.nbt
 This file contains a network-format NBT blob containing entity identifier mappings obtained from `AvailableActorIdentifiersPacket`.
+
+## level_sound_id_map.json
+This file contains a mapping of string sound names to LevelSoundEvent IDs used by LevelSoundEventPacket.
+
+Note that this file may be missing some IDs (it is generated from vanilla using [pmmp/mapping](https://github.com/pmmp/mapping), and vanilla itself is missing some mappings).
+
+## particle_id_map.json
+This file contains a mapping of string particle names to their legacy particle IDs (used for LevelEventPacket). Generated by [pmmp/mapping](https://github.com/pmmp/mapping).