During the Proton feature enhancement I accidentally removed the Steam SDK update stage. This should resolve it so players can view their server in the browser again.
This update allows Risk of Rain 2 to run under Proton and xvfb. This requires the user to run the command below to install prerequisites.
apt-get install xvfb lib32gcc1
This commit enables the use of Risk of Rain 2 servers on Windows only. There is no officially supported way to run on Linux. I'm attempting to solve this through Proton eventually, but it isn't currently an option.