Windows 10 is Windows 9

Widows 10 is Windows 9

While I was testing Windows 10 Technical Preview, I've tried to get into my Microsoft Account by going to the Settings > Accounts > Your Account > Update my Microsoft Account then I was directed to the Microsoft Account's page.

I've noticed the URL is using Platform=Windows9 and not Windows 10:




I don't know why Windows 9 is sitting in the URL but it makes me think that Windows 10 is the direct upgrade version of Windows 8 and Windows 10 is just a name used by Microsoft to make us think that it's a whole new OS.