Great! 🙂
It’s Java based, and AndalayBay released a conversion to Morrowind back in 2014, converting it to C# using WPF with MVVM. She may still have the project files somewhere. The old Bethsoft release threads for Tes4Gecko and the conversion can be viewed in this edited html set.
To edit the Tes4Gecko code in VS 2022/2026 we’ll probably want OpenJDK, there are extensions for VS Code as well. 🙂