diff --git a/.gitmodules b/.gitmodules
index 117285be..ef9d1e78 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -206,3 +206,6 @@
 	path = addons/ncine/module
 	url = https://github.com/nCine/nCine-LuaCATS
 	branch = addon
+[submodule "addons/umbrella-unstable/module"]
+	path = addons/umbrella-unstable/module
+	url = https://github.com/demiurgeQuantified/UmbrellaAddon-Unstable
diff --git a/addons/umbrella-unstable/info.json b/addons/umbrella-unstable/info.json
new file mode 100644
index 00000000..bded602b
--- /dev/null
+++ b/addons/umbrella-unstable/info.json
@@ -0,0 +1,7 @@
+{
+  "$schema": "https://raw.githubusercontent.com/LuaLS/LLS-Addons/main/schemas/addon_info.schema.json",
+  "name": "Umbrella (Unstable)",
+  "description": "Definitions for the Unstable version of Project Zomboid's API",
+  "size": 7396714,
+  "hasPlugin": false
+}
diff --git a/addons/umbrella-unstable/module b/addons/umbrella-unstable/module
new file mode 160000
index 00000000..d3babf52
--- /dev/null
+++ b/addons/umbrella-unstable/module
@@ -0,0 +1 @@
+Subproject commit d3babf52d5f279d513cf653689024b6484dae371