Noticed this while looking into 429s from thumbor, looks like also thumbs for deleted files. e.g.
https://upload.wikimedia.org/wikipedia/commons/thumb/9/94/Mao.jpg/730px-Mao.jpg
Though the file has been deleted: https://commons.wikimedia.org/wiki/File:Mao.jpg
Or https://en.wikipedia.org/wiki/File:Animal_Planet_Canada_Logo.PNG
hive query: select response_size, cache_status, uri_path from wmf.webrequest where webrequest_source='upload' and year = 2017 and month = 6 and day=30 and http_status = '429' limit 10;