Does it mean that the 16-bit NE-related code is forbidden to improve and changes for fixing compatibility with Win3.x/Win9x from developers outside of the project would not be accepted? Just want to know as I do not want to spend time on preparing something, which would not be taken.
They are accepted provided that they fix actual applications that users may want to run. Fixing sample code from Schulman's book is not particularly useful, unless there is evidence that this code has been used in real applications.