It doesn't emulate 9P (protocol); it is in fact the Plan 9 implementation. The fan-in/fan-out of 9p connection is done by 9pserve (src/cmd/9pserve.c, partially emulating the Plan 9 mnt driver.  Servers publish a 9p endpoint, and 9pserve is used to let multiple clients to establish 9p connections to that server.

On Thu, Nov 29, 2018 at 10:02 AM Dan Cross <crossd@gmail.com> wrote:
On Thu, Nov 29, 2018 at 11:43 AM Mayuresh Kathe <mayuresh@kathe.in> wrote:
i apologise up-front for asking this on 9fans, but, how is acme and
plumber and all it's utilities (including upas) made to work under
non-plan9 systems via plan9port; on say something like linux or even mac
os x?

do they have some kind of user-level library which emulates 9p?

That's exactly right.

        - Dan C.