On Windows, \Device\NamedPipe\ is the root directory of the named pipe file system (NPFS), and can be used as RootDirectory to skip its path when accessing the NPFS namespace.
This introduces a regression that makes it possible to use \Device\NamedPipe (note the lack of trailing backslash) as RootDirectory as well, since Wine does not distinguish between \Device\NamedPipe (the device itself) and \Device\NamedPipe\ (the root directory of the filesystem).
(Previous iteration of this patch did distinguish between the two, but the method in which it was implemented was deemed hacky.)