What OS services does Windows UWP Apps for PC uses?

I am doing research on Windows WIA Architecture, and learning how Windows Scan Apps work with different service calls for working with WIA Scanner Services running as Part of STI COM in Svchost.dll. Any Wia app loads Sti.dll COM stub to communicate with Wia service. These makes all sense, unless I bring into picture UWP apps, which is not loading any STI.dll but instead loads something called Windows.Devices.Scanners.dll. Now as per this Windows.Devices.Scanners.dll uses Wia architecture internally to accomplish scan. My question is if UWP is using WIA then why I'm not seeing the usual Wia sta

Question by kishoredbn on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.