failing to download assetbundle manifest object with UnityWebRequest

I can download an assetbundle file via UnityWebRequest without problems, I can load/unload and all. The problem is, I've yet to successfully download a manifest file (same filename with .manifest extension) and use it. In the manual, it is said that this manifest file is another assetbundle file, yet only holds dependency information. I've been trying the same UnityWebRequest to no avail. What am I doing wrong? Below code works when webUri is like this. It doesn't work when it's pointed to a manifest file. I've tried leaving the file as it is, renaming it as a different assetbundle file (without the .manifest extension) nothing works.

 string webUri = "https://Ourwebhosting/AssetBundles/Windows/char1bundle";
 AssetBundle bundle;
 
 using (UnityWebRequest request = UnityWebRequest.GetAssetBundle(webUri, 0))
         {
             yield return request.Send();
             bundle = DownloadHandlerAssetBundle.GetContent(request);
             if (request.error != null)
             {
                 Debug.Log("ERROR:   " + request.error);
             }
             
         }

The error is :

Error while downloading Asset Bundle: Failed to decompress data for the AssetBundle