vscode-remote-oss

That’s the extension which launches the server. The server itself, which is what runs on the remote machine, is part of the vscode repo itself. You can see this open source extension for an example of what the extension does as well as an explanation of what it does https://github.com/xaberus/vscode-remote-oss Mainly just sets up the UI/connect commands in vscode UI and launched REH (the vscode server) on the remote machine. The actual server is just a different binary you build from the same repo. Non-Microsoft OSS builds of vscode work with SSH fine.

I guess that's https://github.com/xaberus/vscode-remote-oss