Distro / Kernel release : Modified Ubuntu 18.04 / 4.15.0-106-lowlatency
Mono / .NET package version : Mono JIT compiler version 6.12.0.107
Graphics driver version : Nvidia 440.82
Works for client, mp server or both : client, other not tested
Installation method used : mono Vintagestory.exe
Hacks (if needed) : I had trouble following mono website instructions, the command
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
didn't finish successfully. So I went to https://keyserver.ubuntu.com/ , entered the key 0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF , notice the 0x added at the beginning, otherwise the key is not found. There just clicked on the first "pub" link to get the public key, downloaded the public key file, just gave it a name "monokey.key" and used the command
sudo apt-key add monokey.key
This in practice replicates what the failing command would do.
And so the rest of the installation process worked fine just as recommended on the mono website.