Fiverr (gig work/task platform, competitor to Upwork) uses a service called Cloudinary to process PDF/images in messaging, including work products from the worker to client.Besides the PDF processing value add, Cloudinary effectively acts like S3 here, serving assets directly to the web client. Like S3, it has support for signed/expiring URLs. However, Fiverr opted to use public URLs, not signed ones, for sensitive client-worker communication.Moreover, it seems like they may be serving public HT...