Microsoft today does not bear much resemblance to the Microsoft of yesteryear, but that aside Microsoft has always been fairly strong on supporting developers and what they want. Microsoft is aware of the way the software development world is going and has been adapting for several years now. They have a lot of major open source projects, and they are actually open source with the full repository and all development being done in the open, which is not a pattern you see that often from large companies opening up their products’ source.
If you’re worried about a for-profit company purchasing your bastion of open-source freedom, remember that GitHub has always been a for-profit company, and was in desperate need of money to prevent it going under and taking your repositories with it until this week.