In other words: there exists some responsible person at Microsoft who violated the copyright (yes, removing the attribution is also a copyright violation!) for Microsoft.

In consideration how Microsoft has been treating copyyright violators for decades, if Microsoft does not give this responsible person the same crual treatment, it should be considered an honest, clear, implicit official statement from Microsoft's side that they are perfectly fine if hackers violate all of Microsoft's copyright. In other words: it means that all of Microsoft's software now (spiritually!) will become public domain.

Also, if Microsot does not make make this responsible person pay the caused damage from their own pocket to the original author of Spegel with the same monatery magnitude as if Microsoft would sue other entities for a violation of copyyright of Microsoft's software, the same statement applies.