Hi, Matt,
It should be easily applicable app under linux, you should have .NET 4.5.2 installed - for example from there:
https://www.microsoft.com/net/download/linux and You can run the exe file under linux. (maybe wine should be required too - i'm not familiar with Linux and those libs from Microsoft are too new for me). If 4.5.2 is too new for linux, I can rebuild it to use .net core 4.5 - someone who is familiar with building .net apps for linux should state there what should be done to run it on the linux.
Secondly, the app is so easy, it should be compilable for Mono (
http://www.mono-project.com/) but I haven´t any linux install near me to test it. If it will be wanted, I will install some debian on the virtual, so I could make and release binaries for Linux too. But as I stated, i will need slight help with this install from experienced user.
According to KML support, please open ticket at GitHub (to be not forgotten), I have KML file format plugin done too, but the file structure is more complex and require more time to finish.