The license has changed from MS-PL to Apache 2.0 relatively recently (it was licensed under MS-PL previously and the change announcement is here). I think you can safely assume it is licensed under Apache 2.0, because this is what the team intends. As far as I can tell, this is just a packaging bug and the license distributed with the installation should be Apache 2.0 too.
I'm not a lawyer, but I think it may be possible to release the code under multiple different licenses if you own it, so it may be the case that legally, the installation is MS-PL licensed and online source is Apache 2 licensed. (Even if it isn't intentional.)
However, both licenses allow you to do essentially the same things, so this shouldn't be a problem.