MissionPlanner VS MahApps.Metro

Run Mission Planner on a PC, connect it to your flight controller, go to "CONFIG", then "full parameter list", then type the first characters of the one you want in the search box on the right.

To add to this, most of the time one doesn't need to hack on the drone firmware itself. Just configuring/hacking the mission planner alone would go a long way: https://ardupilot.org/planner/

But if you're interested in more readable codebases without too much legacy headaches:

https://github.com/BossHobby/QUICKSILVER (for indoor drones mostly)

And for even less functionality but a good learning tool kind of codebase:

https://github.com/nickrehm/dRehmFlight

I want to build a gui to control a small autonomous boat. My initial plan was to modify this thing: https://github.com/ArduPilot/MissionPlanner

If you want to learn how to build it from scratch, you can still look at Arducopter for the firmware. It's entirely open source, including the GCS's like Mission Planner, and you can look at how they implement control over telemetry radios (using a protocol called Mavlink).

Related feature request, )elevation data from the Norwegian Mapping Authority ): https://github.com/ArduPilot/MissionPlanner/issues/2527

You can make a WPF application with VS2022 CE and then install this NuGet package: MahApps

WPF. Controls are highly customizable. Also there are good UI libraries out there, I recommend MahApps.Metro. Also you should take a look at MVVM design pattern.

WPF .NET core 3.1 | Winook| Mahapps

Mahapps.Metro https://mahapps.com/

WPF with https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit or https://github.com/MahApps/MahApps.Metro

MahApps

I've used mahapps ribbon in the past -> https://mahapps.com/