Complex sentence: RAF Alconbury is also the home of the 501st Combat Support Wing (501 CSW), which is the command-and-control authority over geographically separated USAFE units in the United Kingdom.
Split into simpler sentences: RAF Alconbury is also the home of the 501st Combat Support Wing (501 CSW). The 501 CSW is the command and control authority over geographically separated USAFE units in the United Kingdom.