Essex MUD1 by Trubshaw and Bartle
This is a branch of the 1986 BCPL, MACRO-10, and game source files for MUD refactored in Laravel so that the game can be played in a web browser.
There is still some further understanding needed as this mud86 source handles WIZ MODE differently to the mud84 tape and looks for a file that does not currently exist. Still, you can create personas and play the game.
Key differences in game between mud84 (tape) and mud86 (Stamford) version are that fireworks are a thing various events like death are handled differntly so you don't need multiple dead rooms. Hence, this mud86 has 420 rooms compared to 435 rooms in mud84.
The licence for this code is the same as that which Richard Bartle said on 18 May 2020 could be used for the source code: GNU General Public Licence version 3 https://www.gnu.org/licenses/gpl-3.0.html "with a not-for-profit caveat. This means you can do pretty well what you want with it except make money, and if you give it to other people they have to follow the same restrictions."