I don't know if it was developed as part of the development of a new version of Windows or, far more likely, it was simply released with each new version of Win

I don't know if it was developed as part of the development of a new version of Windows or, far more likely, it was simply released with each new version of Windows for maximum impact. IE2 was the first version available for Windows 3.1, Mac OS, etc. Sure it was released at the same time as NT 4.0 but I don't think it was developed with it. The big exception is IE4.0 which was deeply integrated with the Windows 98 shell (hello Active Desktop).