I think this mostly answers your question: https://news.ycombinator.com/item?id=31611208 https://news.ycombinator.com/item?id=31611208 The other part is the co

I think this mostly answers your question: https://news.ycombinator.com/item?id=31611208 https://news.ycombinator.com/item?id=31611208 The other part is the community. People who had backed up their libraries. Devices found on eBay that still had a bunch of apps on them. People who had hoarded IPKs and had them saved on hard drives and were willing to share. That and lots of scraping Google by filename...