For some reason the following Android app code
com.google.api.services.drive.Drive drive;
...
drive.files().list().setQ("mimeType='application/vnd.google-apps.folder' and 'appdata' in parents").execute().getItems();
started returning empty list since May 14. This code was returning my custom folders for more than 1 year before. I can see my App Data content still exists through
https://drive.google.com/drive/my-drive > Settings > Manage Apps.
Any ideas what is wrong?