diff --git a/index.d.ts b/index.d.ts
index a15eda7..aa31c9c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -9,6 +9,7 @@ export type Location = {
 
 export type TreeNode = {
 	name: string;
+	is_anonymous: boolean;
 	children: TreeNode[];
 	locations: Location[];
 }
diff --git a/package-lock.json b/package-lock.json
index e1691c7..2ec5aa3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@projectwallace/css-layer-tree",
-  "version": "1.0.1",
+  "version": "2.0.0-alpha.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@projectwallace/css-layer-tree",
-      "version": "1.0.1",
+      "version": "2.0.0-alpha.0",
       "license": "MIT",
       "dependencies": {
         "css-tree": "^3.0.0"
@@ -19,6 +19,9 @@
         "typescript": "5.4.2",
         "uvu": "^0.5.6",
         "vite": "^5.4.10"
+      },
+      "engines": {
+        "node": ">=18.0.0"
       }
     },
     "node_modules/@actions/core": {
diff --git a/package.json b/package.json
index efb7586..dcea977 100644
--- a/package.json
+++ b/package.json
@@ -1,25 +1,27 @@
 {
   "name": "@projectwallace/css-layer-tree",
-  "version": "1.0.1",
-  "description": "Discover the composition of your CSS @layers",
+  "version": "2.0.0-alpha.0",
+  "description": "Discover the composition of your CSS @layers in a tree-based format.",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/projectwallace/css-layer-tree.git"
   },
+  "author": {
+    "name": "Bart Veneman"
+  },
   "homepage": "https://github.com/projectwallace/css-layer-tree",
   "issues": "https://github.com/projectwallace/css-layer-tree/issues",
   "license": "MIT",
+  "engines": {
+    "node": ">=18.0.0"
+  },
   "type": "module",
-  "source": "src/index.js",
+  "main": "./dist/css-layer-tree.js",
+  "types": "./index.d.ts",
   "exports": {
     "types": "./index.d.ts",
-    "require": "./dist/css-layer-tree.umd.cjs",
     "default": "./dist/css-layer-tree.js"
   },
-  "types": "./index.d.ts",
-  "main": "./dist/css-layer-tree.umd.cjs",
-  "module": "./dist/css-layer-tree.js",
-  "unpkg": "./dist/css-layer-tree.umd.cjs",
   "scripts": {
     "build": "vite build",
     "test": "c8 --reporter=lcov uvu",
diff --git a/vite.config.js b/vite.config.js
index 98692b6..c1eedd2 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -6,20 +6,12 @@ export default defineConfig({
   build: {
     lib: {
       entry: resolve(__dirname, "src/index.js"),
-      name: "cssLayerTree",
-      fileName: "css-layer-tree",
+      formats: ['es']
     },
     rollupOptions: {
       // make sure to externalize deps that shouldn't be bundled
       // into your library
       external: ['css-tree'],
-      output: {
-        // Provide global variables to use in the UMD build
-        // for externalized deps
-        globals: {
-          'css-tree': 'csstree',
-        },
-      },
     },
   },
   plugins: [