Perhaps they are referring to the Android app that displays this "Extended metadata" window?
In Mp3tag you can call the metadata window clicking on View -> Extended Tags.
If you use Mp3tag and ensure that you write your metadata in one of the ID3v2 versions I don't see why this should not work for you Android App.
Please make sure that you are using either the ID3v2.3 or the ID3v2.4 version for your MP3 files in File -> Options -> Tags -> Mpeg:
