As the name suggests this tool can be used to view/check the techtree. It directly parses the rule files, so if there is a missing/superfluous dependency or something, you can see it there. You just go to File->Import->OpenXCom Research and select the game's folder.
It is based on a normal graph-making tool that is still fully functional and can be used to build all sorts of graphs.
The source is on GitHub:
https://github.com/bohemond-of-antioch/OpenXcom-TechTreeViewerA compiled version for windows is attached.
It's VB.NET again, I apologize to the linux users in advance.
I made the configuration file a yaml as that's a format everyone here should be familliar with. A few things can be configured there, mostly colors.
I'm releasing this under Creative Commons Zero.