What is missing from Linux support?

I saw the answer to: What is the current status of Linux support? - Platform & Builds - Epic Developer Community Forums

If someone wanted to port the engine for Linux, how large effort would it be? Do you have platform specific code separated?

Does the engine require anything that’s not in libsdl2 and opengl?

Code available currently only supports Linux as a dedicated server platform, so no SDL2 yet, although this is coming pretty soon. We do have the platform abstraction layer, so you are free to fill in missing bits - but I advise waiting for the next few releases for the client support.