I work on the team doing Visual Studio's Tools for Apache Cordova. While I don't work on the open-source side of the fence, we have engineers focused on contributing to Cordova.
Search the mailing list for "microsoft" (which picks up e-mail addresses) compared to "windows" to see where MS involvement picked up.[1]
A lot of Microsoft's involvements in open source are via MS Open Tech. See their website for more information about their contributions.[2] While this doesn't show checkins, here are their blog posts about Cordova.[3]
[1] http://callback.markmail.org/search/?q=list%3Aorg.apache.inc...