https://www.theregister.co.uk/2018/08/21/bing_runs_on_net_core_21/

Microsoft's Bing search engine now runs on an open-source platform - .NET Core 2.1, to be precise.

Famous for chowing down on its own dog food, Microsoft's admission is not altogether surprising. What does raise a bushy eyebrow is how capable it shows the open-sourced framework to be.