PUEBLO  [protocol]
The older HTML-in-a-MUD scheme, from the client of the same name. Still
supported by MUSH-side clients, and routinely confused with MXP.
https://pueblo.sourceforge.net/

Measured adoption
  0 of 886 listed games were observed offering it (0.0%)
  /games?protocol=PUEBLO

  The games not counted here are not games without the protocol. A game is
  counted when we observed its server offering the option in a handshake; the
  rest are servers that did not offer it to us and servers whose handshake we
  have not read, and we cannot tell you which.

  By codebase, of the games we identified
    AresMUSH             0 of 18 offered it
    CircleMUD            0 of 47 offered it
    CobraMUSH            0 of 2 offered it
    CoffeeMUD            0 of 32 offered it
    DikuMUD              0 of 34 offered it
    Evennia              0 of 11 offered it
    FluffOS              0 of 28 offered it
    MUCK                 0 of 24 offered it
    PennMUSH             0 of 34 offered it
    RhostMUSH            0 of 40 offered it
    ROM                  0 of 55 offered it
    SMAUG                0 of 20 offered it
    tbaMUD               0 of 5 offered it
    TinyMUSH             0 of 9 offered it

Pueblo came out of the client of the same name in the mid-nineties and took a
direct approach to enhancing MUD text: let the server send HTML, and let the
client render it. A server announces Pueblo support in a line at connect; the
client replies, and from then on the stream may carry markup.

It reached the MUSH side of the hobby more than the MUD side, and MUSH servers
that support it generally still do.

NOT MXP

MXP [/reference/protocols/mxp] is the later scheme and the more widely
implemented one. They do a similar job and are not compatible, and reading a
client's Pueblo support as MXP support — or the reverse — is the single easiest
mistake to make when compiling a client comparison. The client pages in this
section keep them separate for that reason, and where a project documents one
and not the other, the other says unknown.

WHAT WE MEASURE

Pueblo's handshake is not a telnet option in the usual sense, so what we observe
is narrower than for the negotiated protocols, and a low figure here should be
read as a statement about our visibility rather than about deployment.

See also
  MXP — /reference/protocols/mxp
  BeipMU — /reference/clients/beipmu