Quick question: What is V5 VEXos, and what does it do?

VEXos is the operating system for the VEX IQ Robot Brain, and upon its release, the V5 Robot Brain. Similar to any smartphone OS, VEXos will be periodically updated to add new features, fix bugs, etc.

You can find a bit more information here:

There is a description of VEXos functionality for V5 here