From your source: "Microsoft's internal project name for the new OS was OS/2 NT, because Microsoft's intention was for the new OS to succeed OS/2 yet retain the OS/2 API as
its primary interface."
Note how Russinovich talks about a "new OS".
The NT (kernel) never had any OS/2 code in it, it was a totally different project. The first target processor architecture for NT wasn't even x86, it was MIPS.
OS/2 in NT was merely a subsystem layer next to DOS and Posix, somewhat like today there is the Linux subsystem layer in Windows 10.
From your source: "Microsoft's internal project name for the new OS was OS/2 NT, because Microsoft's intention was for the new OS to succeed OS/2 yet retain the OS/2 API as its primary interface."
Note how Russinovich talks about a "new OS".
The NT (kernel) never had any OS/2 code in it, it was a totally different project. The first target processor architecture for NT wasn't even x86, it was MIPS.
OS/2 in NT was merely a subsystem layer next to DOS and Posix, somewhat like today there is the Linux subsystem layer in Windows 10.
A good source is this:
https://www.amazon.com/Show-Stopper-Breakneck-Generation-Mic...