diff --git a/lib/assets/assetManager.ts b/lib/assets/assetManager.ts
index 5784bfa..3d5525b 100644
--- a/lib/assets/assetManager.ts
+++ b/lib/assets/assetManager.ts
@@ -38,6 +38,7 @@ export class AssetManager {
   private readonly allowed: Set<string>
   private byHash = new Map<string, AssetRef>()
   private byOriginal = new Map<string, string>() // originalName -> path
+  private referenced = new Set<string>() // originalName referenced via rewrite
 
   constructor(opts: AssetManagerOptions) {
     this.maxBytes = opts.maxBytes
@@ -91,8 +92,13 @@ export class AssetManager {
     if (urlOrLocalRef.startsWith('local:')) {
       const key = urlOrLocalRef.slice('local:'.length)
       const p = this.byOriginal.get(key)
+      if (p) this.referenced.add(key)
       return p ?? urlOrLocalRef
     }
     return urlOrLocalRef
   }
+
+  referencedList(): string[] {
+    return Array.from(this.referenced)
+  }
 }
diff --git a/lib/exporter/assets.meta.ts b/lib/exporter/assets.meta.ts
index 4170ebc..eb36f7f 100644
--- a/lib/exporter/assets.meta.ts
+++ b/lib/exporter/assets.meta.ts
@@ -8,13 +8,22 @@ export type AssetMetaItem = {
   ext: string
   zipPath: string
   integrity: string
+  group: 'images' | 'fonts' | 'other'
+  referencedAt: string[]
 }
 
 export function buildAssetsMetadata(am: AssetManager): Uint8Array {
   const list = am.list()
+  const referenced = new Set(am.referencedList())
   const items: AssetMetaItem[] = list.map((ref) => {
     // Browser-safe synchronous integrity: base64 of bytes as placeholder
     const b64 = Buffer.from(ref.bytes).toString('base64')
+    const group: 'images' | 'fonts' | 'other' = ref.mimeType.startsWith('image/')
+      ? 'images'
+      : ref.mimeType.startsWith('font/')
+      ? 'fonts'
+      : 'other'
+    const referencedAt = referenced.has(ref.originalName) ? [`local:${ref.originalName}`] : []
     return {
       originalName: ref.originalName,
       mimeType: ref.mimeType,
@@ -23,6 +32,8 @@ export function buildAssetsMetadata(am: AssetManager): Uint8Array {
       ext: ref.ext,
       zipPath: ref.path,
       integrity: `sha256-${b64}`,
+      group,
+      referencedAt,
     }
   })
   const json = JSON.stringify({ assets: items }, null, 2)