If you run the app, click on the "tools and options" cog then "licences". This page lists a lot of libraries.
> Apparently this is written in C#.
You sound surprised. To me it looks like a quite slick WPF app, which aims for a metro-ish look. But I've seen nothing in the UI that is particularly challenging for WPF. WPF is very, very flexible.
> I assumed that doing any sort of integration with Git would require C-level bridging.
Short of re-writing git in c#, it does require bridging. That's what unsafe code is for - calling out to dlls written in c.
> Didn't realise there was any sort of decent C# bindings for Git.
I kind of just assumed that there was. There usually is. The licences page lists "libgit2", so it's probably this one: https://github.com/libgit2/libgit2sharp#readme (edit yep, LibGit2Sharp is mentioned later on in the licences)
The file LibGit2Sharp/Core/NativeMethods.cs seems to do a lot of the bindings.
> the WPF ones that I've seen were quite clunky
I said that WPF was flexible, I didn't say simple or easy :P Also, to get good design, you usually need the help of a designer. Most coders will produce "clunky" UIs. I would. Somehow, the Windows desktop space has been very slow to deal with this.
> Apparently this is written in C#.
You sound surprised. To me it looks like a quite slick WPF app, which aims for a metro-ish look. But I've seen nothing in the UI that is particularly challenging for WPF. WPF is very, very flexible.