Actually, I think IE is based on the Spyglass browser, which is probably only a distant cousin at this point to Mosaic.
Have a look at IE's help menu.
BTW: Has anybody considered that the BSD TCP stack may be easier to port to ReactOS? I work with another open-source operating system called eCos, and it uses the BSD networking stack but its design is not like a traditional UNIX kernel.
Actually NT's stack is said to be taken from BSD.