Could you clarify why this is necessary? The original issue says:

Required for X-Window and prevents ownership bugs with git.

I haven't had issues related to UIDs before when running X11 applications inside a Docker container that connect to an XServer on the host.

Regarding file permissions: The VSCode docs say that if a Dockerfile is given in the devcontainer config, it will automatically inject the UID of the current user (on a Linux host). So there should be no need to hardcode UID=1000?

https://aka.ms/vscode-remote/containers/non-root

On Linux, if you are referencing a Dockerfile or image in devcontainer.json, this will also automatically update the container user's UID/GID to match your local user to avoid the bind mount permissions problem that exists in this environment (unless you set "updateRemoteUserUID": false).

(I'm not sure if this requires setting the remoteUser configuration option)

What is the status of this issue? Does anyone need the container user to be non-root, or can we close this?

As just discussed with @rs22 we close this one until somebody needs it again.