SMAUG  [codebase]
A Merc derivative built for large themed worlds, with deities, planes and an
area set several times the size of its parent's.
https://www.smaug.org/

Games we have identified as running this codebase
  20 listed, 0 archived
  /games?codebase=SMAUG
  Measured in their handshakes: MSDP, MSSP, MXP, MCCP, CHARSET, UTF-8

SMAUG — Simulated Medieval Adventure multi-User Game — came out of the Realms of
Despair and is a Merc derivative that grew rather than simplified. Where ROM
tightened Merc's combat, SMAUG added: deities, planes, more elaborate area and
mob programs, a much larger stock world, and a correspondingly larger source
tree.

Games running it tend to be the big themed ones, and several have been running
continuously for twenty-five years.

WHAT IT LOOKS LIKE FROM OUTSIDE

MSSP, answered on request, and nothing else negotiated on the game we measured.

Note for anyone comparing counts: SMAUG servers in our survey reported through
MSSP and did not answer a login-screen WHO, so the number here is the game's own
MSSP PLAYERS — an assertion the server makes, taken at face value only because
we could not measure it independently. The game page labels which of the two any
given figure came from.

See also
  DikuMUD — /reference/codebases/dikumud
  ROM — /reference/codebases/rom