What does HackerNews think of calculator?
Windows Calculator: A simple yet powerful calculator that ships with Windows
Language:
C++
Is it? Just opened it on Windows 10 and it opens instantly and uses 23MB of RAM which is rather low for a modern application. Calculator is also fully open source now.
the new calculator app is open source, you can see what's making it so slow if you want, and contribute fixes if you have the skills to do the fixing.
MIT license.
Nope, that is the UWP security container most likely.