I can confirm with a very little spelunking that the Mac app is a real native AppKit/Cocoa app. It appears to mostly be written in Swift, but also uses a fair a

I can confirm with a very little spelunking that the Mac app is a real native AppKit/Cocoa app. It appears to mostly be written in Swift, but also uses a fair amount of Objective-C. They've said publicly that the Windows version is written in C# and C/C++. Not sure what they did for Linux...