That effort, TypeScript, which was codenamed "Strada" (see more on the codename below), is available in preview form on Microsoft's CodePlex site. The open-source TypeScript compiler and the spec are there, as is a plug-in for Visual Studio.
Even though its roots seemingly are in Internet Explorer, which is part of the Windows client division, the TypeScript team sits in Microsoft's Developer Division.
The most publicly recognizable name behind TypeScript is Microsoft Technical Fellow Anders Hejlsberg, the father of C# and TurboPascal. But Hejlsberg isn't the one who came up with the idea for TypeScript.
Yet another notable on the TypeScript team is someone Microsoft officials haven't mentioned in a while. Erich Gamma, a high-profile hire from IBM who joined Microsoft in 2011. Gamma is a Distinguished Engineer in Microsoft Zurich. He used to be the technical lead of IBM's Rational Collaborative Application Life Cycle management work and also the former technical lead of Rational Team Concert. Additionally, he was the original lead of the Eclipse Java development environment and one of the leaders of the Eclipse Project.
When he joined Microsoft in 2011, Microsoft officials didn't say exactly what he'd be working on. They did say he'd continue to operate out of Zurich, Switzerland, where Microsoft would be "opening a small Visual Studio development lab with Erich as the lead."
It turns out Gamma is also part of the TypeScript team, as can be seen by his GibHub commit to change the name of TypeScript from its codename, Strada.