RTC-Git integration with Node.js - how is REMOTE_USER env var set?

RTC 6.0.1. Server is Mint Linux. Client is windows with eclipse 4.2 RTC client.

As part of the node.js code called by the hooks, in ValidatePush.js, is this code

function computeData()
{
        var data = {};
        data.gitUser = thisProcess.env["REMOTE_USER"];

This results in gitUser being undefined which causes an Invalid input error.

REMOTE_USER is set in services/GitBackendService.js but that does not seem to be called. Looking at that code, I think it is supposed to be called by main.js which is the server running in the background. But that is not happening.

Could this be because I am using ssh to push with rather than http which would be going via the node.js server?

Does anyone have any more information on this?